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1 | /* |
2 | * Copyright (c) 2015 Apple Inc. All rights reserved. | |
3 | * | |
4 | * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ | |
5 | * | |
6 | * This file contains Original Code and/or Modifications of Original Code | |
7 | * as defined in and that are subject to the Apple Public Source License | |
8 | * Version 2.0 (the 'License'). You may not use this file except in | |
9 | * compliance with the License. The rights granted to you under the License | |
10 | * may not be used to create, or enable the creation or redistribution of, | |
11 | * unlawful or unlicensed copies of an Apple operating system, or to | |
12 | * circumvent, violate, or enable the circumvention or violation of, any | |
13 | * terms of an Apple operating system software license agreement. | |
14 | * | |
15 | * Please obtain a copy of the License at | |
16 | * http://www.opensource.apple.com/apsl/ and read it before using this file. | |
17 | * | |
18 | * The Original Code and all software distributed under the License are | |
19 | * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER | |
20 | * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, | |
21 | * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, | |
22 | * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. | |
23 | * Please see the License for the specific language governing rights and | |
24 | * limitations under the License. | |
25 | * | |
26 | * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ | |
27 | */ | |
28 | /* | |
29 | * @OSF_FREE_COPYRIGHT@ | |
30 | */ | |
31 | /* | |
32 | * Mach Operating System | |
33 | * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University | |
34 | * All Rights Reserved. | |
35 | * | |
36 | * Permission to use, copy, modify and distribute this software and its | |
37 | * documentation is hereby granted, provided that both the copyright | |
38 | * notice and this permission notice appear in all copies of the | |
39 | * software, derivative works or modified versions, and any portions | |
40 | * thereof, and that both notices appear in supporting documentation. | |
41 | * | |
42 | * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" | |
43 | * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR | |
44 | * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. | |
45 | * | |
46 | * Carnegie Mellon requests users of this software to return to | |
47 | * | |
48 | * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU | |
49 | * School of Computer Science | |
50 | * Carnegie Mellon University | |
51 | * Pittsburgh PA 15213-3890 | |
52 | * | |
53 | * any improvements or extensions that they make and grant Carnegie Mellon | |
54 | * the rights to redistribute these changes. | |
55 | */ | |
56 | #include <kern/ast.h> | |
57 | #include <kern/kern_types.h> | |
58 | #include <kern/mach_param.h> | |
59 | #include <kern/queue.h> | |
60 | #include <kern/sched_prim.h> | |
61 | #include <kern/simple_lock.h> | |
62 | #include <kern/spl.h> | |
63 | #include <kern/waitq.h> | |
64 | #include <kern/zalloc.h> | |
65 | #include <libkern/OSAtomic.h> | |
66 | #include <mach/sync_policy.h> | |
67 | #include <vm/vm_kern.h> | |
68 | ||
69 | #include <sys/kdebug.h> | |
70 | ||
71 | #if CONFIG_WAITQ_DEBUG | |
72 | #define wqdbg(fmt,...) \ | |
73 | printf("WQ[%s]: " fmt "\n", __func__, ## __VA_ARGS__) | |
74 | #else | |
75 | #define wqdbg(fmt,...) do { } while (0) | |
76 | #endif | |
77 | ||
78 | #ifdef WAITQ_VERBOSE_DEBUG | |
79 | #define wqdbg_v(fmt,...) \ | |
80 | printf("WQ[v:%s]: " fmt "\n", __func__, ## __VA_ARGS__) | |
81 | #else | |
82 | #define wqdbg_v(fmt,...) do { } while (0) | |
83 | #endif | |
84 | ||
85 | #define wqinfo(fmt,...) \ | |
86 | printf("WQ[%s]: " fmt "\n", __func__, ## __VA_ARGS__) | |
87 | ||
88 | #define wqerr(fmt,...) \ | |
89 | printf("WQ[%s] ERROR: " fmt "\n", __func__, ## __VA_ARGS__) | |
90 | ||
91 | ||
92 | /* | |
93 | * un-comment the following lines to debug the link/prepost tables | |
94 | * NOTE: this expands each element by ~40 bytes | |
95 | */ | |
96 | //#define CONFIG_WAITQ_LINK_STATS | |
97 | //#define CONFIG_WAITQ_PREPOST_STATS | |
98 | ||
99 | /* | |
100 | * file-static functions / data | |
101 | */ | |
102 | static thread_t waitq_select_one_locked(struct waitq *waitq, event64_t event, | |
103 | uint64_t *reserved_preposts, | |
104 | int priority, spl_t *spl); | |
105 | ||
106 | static kern_return_t waitq_select_thread_locked(struct waitq *waitq, | |
107 | event64_t event, | |
108 | thread_t thread, spl_t *spl); | |
109 | ||
110 | #define WAITQ_SET_MAX (task_max * 3) | |
111 | static zone_t waitq_set_zone; | |
112 | ||
113 | ||
114 | #define P2ROUNDUP(x, align) (-(-((uint32_t)(x)) & -(align))) | |
115 | #define ROUNDDOWN(x,y) (((x)/(y))*(y)) | |
116 | ||
117 | ||
118 | #ifdef CONFIG_WAITQ_STATS | |
119 | static __inline__ void waitq_grab_backtrace(uintptr_t bt[NWAITQ_BTFRAMES], int skip); | |
120 | #endif | |
121 | ||
122 | ||
123 | /* ---------------------------------------------------------------------- | |
124 | * | |
125 | * Wait Queue Link/Prepost Table Implementation | |
126 | * | |
127 | * ---------------------------------------------------------------------- */ | |
128 | #define DEFAULT_MIN_FREE_TABLE_ELEM 100 | |
129 | static uint32_t g_min_free_table_elem; | |
130 | static uint32_t g_min_free_cache; | |
131 | ||
132 | static vm_size_t g_wqt_max_tbl_size; | |
133 | static lck_grp_t g_wqt_lck_grp; | |
134 | ||
135 | /* 1 prepost table, 1 setid link table */ | |
136 | #define NUM_WQ_TABLES 2 | |
137 | ||
138 | /* default VA space for waitq tables (zone allocated) */ | |
139 | #define DEFAULT_MAX_TABLE_SIZE P2ROUNDUP(8 * 1024 * 1024, PAGE_SIZE) | |
140 | ||
141 | struct wq_id { | |
142 | union { | |
143 | uint64_t id; | |
144 | struct { | |
145 | /* | |
146 | * this bitfied is OK because we don't need to | |
147 | * enforce a particular memory layout | |
148 | */ | |
149 | uint64_t idx:18, /* allows indexing up to 8MB of 32byte link objects */ | |
150 | generation:46; | |
151 | }; | |
152 | }; | |
153 | }; | |
154 | ||
155 | enum wqt_elem_type { | |
156 | WQT_FREE = 0, | |
157 | WQT_ELEM = 1, | |
158 | WQT_LINK = 2, | |
159 | WQT_RESERVED = 3, | |
160 | }; | |
161 | ||
162 | struct wqt_elem { | |
163 | uint32_t wqt_bits; | |
164 | ||
165 | uint32_t wqt_next_idx; | |
166 | ||
167 | struct wq_id wqt_id; | |
168 | }; | |
169 | ||
170 | /* this _must_ match the idx bitfield definition in struct wq_id */ | |
171 | #define WQT_IDX_MAX (0x3ffff) | |
172 | #if defined(DEVELOPMENT) || defined(DEBUG) | |
173 | /* global for lldb macros */ | |
174 | uint64_t g_wqt_idx_max = WQT_IDX_MAX; | |
175 | #endif | |
176 | ||
177 | /* reference count bits should _always_ be the low-order bits */ | |
178 | #define WQT_BITS_REFCNT_MASK (0x1FFFFFFF) | |
179 | #define WQT_BITS_REFCNT_SHIFT (0) | |
180 | #define WQT_BITS_REFCNT (WQT_BITS_REFCNT_MASK << WQT_BITS_REFCNT_SHIFT) | |
181 | ||
182 | #define WQT_BITS_TYPE_MASK (0x3) | |
183 | #define WQT_BITS_TYPE_SHIFT (29) | |
184 | #define WQT_BITS_TYPE (WQT_BITS_TYPE_MASK << WQT_BITS_TYPE_SHIFT) | |
185 | ||
186 | #define WQT_BITS_VALID_MASK (0x1) | |
187 | #define WQT_BITS_VALID_SHIFT (31) | |
188 | #define WQT_BITS_VALID (WQT_BITS_VALID_MASK << WQT_BITS_VALID_SHIFT) | |
189 | ||
190 | #define wqt_bits_refcnt(bits) \ | |
191 | (((bits) >> WQT_BITS_REFCNT_SHIFT) & WQT_BITS_REFCNT_MASK) | |
192 | ||
193 | #define wqt_bits_type(bits) \ | |
194 | (((bits) >> WQT_BITS_TYPE_SHIFT) & WQT_BITS_TYPE_MASK) | |
195 | ||
196 | #define wqt_bits_valid(bits) \ | |
197 | ((bits) & WQT_BITS_VALID) | |
198 | ||
199 | struct wq_table; | |
200 | typedef void (*wq_table_poison_func)(struct wq_table *, struct wqt_elem *); | |
201 | ||
202 | /* | |
203 | * A table is a container for slabs of elements. Each slab is 'slab_sz' bytes | |
204 | * and contains 'slab_sz/elem_sz' elements (of 'elem_sz' bytes each). These | |
205 | * slabs allow the table to be broken up into potentially dis-contiguous VA | |
206 | * space. On 32-bit platforms with large amounts of physical RAM, this is | |
207 | * quite important. Keeping slabs like this slightly complicates retrieval of | |
208 | * table elements, but not by much. | |
209 | */ | |
210 | struct wq_table { | |
211 | struct wqt_elem **table; /* an array of 'slabs' of elements */ | |
212 | struct wqt_elem **next_free_slab; | |
213 | struct wq_id free_list __attribute__((aligned(8))); | |
214 | ||
215 | uint32_t nelem; | |
216 | uint32_t used_elem; | |
217 | uint32_t elem_sz; /* size of a table element (bytes) */ | |
218 | ||
219 | uint32_t slab_sz; /* size of a table 'slab' object (bytes) */ | |
220 | uint32_t slab_shift; | |
221 | uint32_t slab_msk; | |
222 | uint32_t slab_elem; | |
223 | zone_t slab_zone; | |
224 | ||
225 | wq_table_poison_func poison; | |
226 | ||
227 | lck_mtx_t lock; | |
228 | uint32_t state; | |
229 | ||
230 | #if CONFIG_WAITQ_STATS | |
231 | uint32_t nslabs; | |
232 | ||
233 | uint64_t nallocs; | |
234 | uint64_t nreallocs; | |
235 | uint64_t npreposts; | |
236 | int64_t nreservations; | |
237 | uint64_t nreserved_releases; | |
238 | uint64_t nspins; | |
239 | ||
240 | uint64_t max_used; | |
241 | uint64_t avg_used; | |
242 | uint64_t max_reservations; | |
243 | uint64_t avg_reservations; | |
244 | #endif | |
245 | } __attribute__((aligned(8))); | |
246 | ||
247 | #define wqt_elem_ofst_slab(slab, slab_msk, ofst) \ | |
248 | /* cast through 'void *' to avoid compiler alignment warning messages */ \ | |
249 | ((struct wqt_elem *)((void *)((uintptr_t)(slab) + ((ofst) & (slab_msk))))) | |
250 | ||
251 | #if defined(CONFIG_WAITQ_LINK_STATS) || defined(CONFIG_WAITQ_PREPOST_STATS) | |
252 | /* version that makes no assumption on waste within a slab */ | |
253 | static inline struct wqt_elem * | |
254 | wqt_elem_idx(struct wq_table *table, uint32_t idx) | |
255 | { | |
256 | int slab_idx = idx / table->slab_elem; | |
257 | struct wqt_elem *slab = table->table[slab_idx]; | |
258 | if (!slab) | |
259 | panic("Invalid index:%d slab:%d (NULL) for table:%p\n", | |
260 | idx, slab_idx, table); | |
261 | assert(slab->wqt_id.idx <= idx && (slab->wqt_id.idx + table->slab_elem) > idx); | |
262 | return wqt_elem_ofst_slab(slab, table->slab_msk, (idx - slab->wqt_id.idx) * table->elem_sz); | |
263 | } | |
264 | #else /* !CONFIG_WAITQ_[LINK|PREPOST]_STATS */ | |
265 | /* verion that assumes 100% ultilization of slabs (no waste) */ | |
266 | static inline struct wqt_elem * | |
267 | wqt_elem_idx(struct wq_table *table, uint32_t idx) | |
268 | { | |
269 | uint32_t ofst = idx * table->elem_sz; | |
270 | struct wqt_elem *slab = table->table[ofst >> table->slab_shift]; | |
271 | if (!slab) | |
272 | panic("Invalid index:%d slab:%d (NULL) for table:%p\n", | |
273 | idx, (ofst >> table->slab_shift), table); | |
274 | assert(slab->wqt_id.idx <= idx && (slab->wqt_id.idx + table->slab_elem) > idx); | |
275 | return wqt_elem_ofst_slab(slab, table->slab_msk, ofst); | |
276 | } | |
277 | #endif /* !CONFIG_WAITQ_[LINK|PREPOST]_STATS */ | |
278 | ||
279 | static int __assert_only wqt_elem_in_range(struct wqt_elem *elem, | |
280 | struct wq_table *table) | |
281 | { | |
282 | struct wqt_elem **base = table->table; | |
283 | uintptr_t e = (uintptr_t)elem; | |
284 | assert(base != NULL); | |
285 | while (*base != NULL) { | |
286 | uintptr_t b = (uintptr_t)(*base); | |
287 | if (e >= b && e < b + table->slab_sz) | |
288 | return 1; | |
289 | base++; | |
290 | if ((uintptr_t)base >= (uintptr_t)table->table + PAGE_SIZE) | |
291 | return 0; | |
292 | } | |
293 | return 0; | |
294 | } | |
295 | ||
296 | static struct wqt_elem *wq_table_get_elem(struct wq_table *table, uint64_t id); | |
297 | static void wq_table_put_elem(struct wq_table *table, struct wqt_elem *elem); | |
298 | static int wqt_elem_list_link(struct wq_table *table, struct wqt_elem *parent, | |
299 | struct wqt_elem *child); | |
300 | ||
301 | static void wqt_elem_invalidate(struct wqt_elem *elem) | |
302 | { | |
303 | uint32_t __assert_only old = OSBitAndAtomic(~WQT_BITS_VALID, &elem->wqt_bits); | |
304 | OSMemoryBarrier(); | |
305 | assert(((wqt_bits_type(old) != WQT_RESERVED) && (old & WQT_BITS_VALID)) || | |
306 | ((wqt_bits_type(old) == WQT_RESERVED) && !(old & WQT_BITS_VALID))); | |
307 | } | |
308 | ||
309 | static void wqt_elem_mkvalid(struct wqt_elem *elem) | |
310 | { | |
311 | uint32_t __assert_only old = OSBitOrAtomic(WQT_BITS_VALID, &elem->wqt_bits); | |
312 | OSMemoryBarrier(); | |
313 | assert(!(old & WQT_BITS_VALID)); | |
314 | } | |
315 | ||
316 | static void wqt_elem_set_type(struct wqt_elem *elem, int type) | |
317 | { | |
318 | uint32_t old_bits, new_bits; | |
319 | do { | |
320 | old_bits = elem->wqt_bits; | |
321 | new_bits = (old_bits & ~WQT_BITS_TYPE) | | |
322 | ((type & WQT_BITS_TYPE_MASK) << WQT_BITS_TYPE_SHIFT); | |
323 | } while (OSCompareAndSwap(old_bits, new_bits, &elem->wqt_bits) == FALSE); | |
324 | OSMemoryBarrier(); | |
325 | } | |
326 | ||
327 | ||
328 | static void wq_table_bootstrap(void) | |
329 | { | |
330 | uint32_t tmp32 = 0; | |
331 | ||
332 | g_min_free_cache = 0; | |
333 | g_min_free_table_elem = DEFAULT_MIN_FREE_TABLE_ELEM; | |
334 | if (PE_parse_boot_argn("wqt_min_free", &tmp32, sizeof(tmp32)) == TRUE) | |
335 | g_min_free_table_elem = tmp32; | |
336 | wqdbg("Minimum free table elements: %d", tmp32); | |
337 | ||
338 | g_wqt_max_tbl_size = DEFAULT_MAX_TABLE_SIZE; | |
339 | if (PE_parse_boot_argn("wqt_tbl_size", &tmp32, sizeof(tmp32)) == TRUE) | |
340 | g_wqt_max_tbl_size = (vm_size_t)P2ROUNDUP(tmp32, PAGE_SIZE); | |
341 | ||
342 | lck_grp_init(&g_wqt_lck_grp, "waitq_table_locks", LCK_GRP_ATTR_NULL); | |
343 | } | |
344 | ||
345 | static void wq_table_init(struct wq_table *table, const char *name, | |
346 | uint32_t max_tbl_elem, uint32_t elem_sz, | |
347 | wq_table_poison_func poison) | |
348 | { | |
349 | kern_return_t kr; | |
350 | uint32_t slab_sz, slab_shift, slab_msk, slab_elem; | |
351 | zone_t slab_zone; | |
352 | size_t max_tbl_sz; | |
353 | struct wqt_elem *e, **base; | |
354 | ||
355 | /* | |
356 | * First, allocate a single page of memory to act as the base | |
357 | * for the table's element slabs | |
358 | */ | |
359 | kr = kernel_memory_allocate(kernel_map, (vm_offset_t *)&base, | |
360 | PAGE_SIZE, 0, KMA_NOPAGEWAIT, VM_KERN_MEMORY_WAITQ); | |
361 | if (kr != KERN_SUCCESS) | |
362 | panic("Cannot initialize %s table: " | |
363 | "kernel_memory_allocate failed:%d\n", name, kr); | |
364 | memset(base, 0, PAGE_SIZE); | |
365 | ||
366 | /* | |
367 | * Based on the maximum table size, calculate the slab size: | |
368 | * we allocate 1 page of slab pointers for the table, and we need to | |
369 | * index elements of 'elem_sz', this gives us the slab size based on | |
370 | * the maximum size the table should grow. | |
371 | */ | |
372 | max_tbl_sz = (max_tbl_elem * elem_sz); | |
373 | max_tbl_sz = P2ROUNDUP(max_tbl_sz, PAGE_SIZE); | |
374 | ||
375 | /* system maximum table size divided by number of slots in a page */ | |
376 | slab_sz = (uint32_t)(max_tbl_sz / (PAGE_SIZE / (sizeof(void *)))); | |
377 | if (slab_sz < PAGE_SIZE) | |
378 | slab_sz = PAGE_SIZE; | |
379 | ||
380 | /* make sure the slab size is a power of two */ | |
381 | slab_shift = 0; | |
382 | slab_msk = ~0; | |
383 | for (uint32_t i = 0; i < 31; i++) { | |
384 | uint32_t bit = (1 << i); | |
385 | if ((slab_sz & bit) == slab_sz) { | |
386 | slab_shift = i; | |
387 | slab_msk = 0; | |
388 | for (uint32_t j = 0; j < i; j++) | |
389 | slab_msk |= (1 << j); | |
390 | break; | |
391 | } | |
392 | slab_sz &= ~bit; | |
393 | } | |
394 | slab_elem = slab_sz / elem_sz; | |
395 | ||
396 | /* initialize the table's slab zone (for table growth) */ | |
397 | wqdbg("Initializing %s zone: slab:%d (%d,0x%x) max:%ld", | |
398 | name, slab_sz, slab_shift, slab_msk, max_tbl_sz); | |
399 | slab_zone = zinit(slab_sz, max_tbl_sz, slab_sz, name); | |
400 | assert(slab_zone != ZONE_NULL); | |
401 | ||
402 | /* allocate the first slab and populate it */ | |
403 | base[0] = (struct wqt_elem *)zalloc(slab_zone); | |
404 | if (base[0] == NULL) | |
405 | panic("Can't allocate a %s table slab from zone:%p", | |
406 | name, slab_zone); | |
407 | ||
408 | memset(base[0], 0, slab_sz); | |
409 | ||
410 | /* setup the initial freelist */ | |
411 | wqdbg("initializing %d links (%d bytes each)...", slab_elem, elem_sz); | |
412 | for (unsigned l = 0; l < slab_elem; l++) { | |
413 | e = wqt_elem_ofst_slab(base[0], slab_msk, l * elem_sz); | |
414 | e->wqt_id.idx = l; | |
415 | /* | |
416 | * setting generation to 0 ensures that a setid of 0 is | |
417 | * invalid because the generation will be incremented before | |
418 | * each element's allocation. | |
419 | */ | |
420 | e->wqt_id.generation = 0; | |
421 | e->wqt_next_idx = l + 1; | |
422 | } | |
423 | ||
424 | /* make sure the last free element points to a never-valid idx */ | |
425 | e = wqt_elem_ofst_slab(base[0], slab_msk, (slab_elem - 1) * elem_sz); | |
426 | e->wqt_next_idx = WQT_IDX_MAX; | |
427 | ||
428 | lck_mtx_init(&table->lock, &g_wqt_lck_grp, LCK_ATTR_NULL); | |
429 | ||
430 | table->slab_sz = slab_sz; | |
431 | table->slab_shift = slab_shift; | |
432 | table->slab_msk = slab_msk; | |
433 | table->slab_elem = slab_elem; | |
434 | table->slab_zone = slab_zone; | |
435 | ||
436 | table->elem_sz = elem_sz; | |
437 | table->nelem = slab_elem; | |
438 | table->used_elem = 0; | |
439 | table->elem_sz = elem_sz; | |
440 | table->poison = poison; | |
441 | ||
442 | table->table = base; | |
443 | table->next_free_slab = &base[1]; | |
444 | table->free_list.id = base[0]->wqt_id.id; | |
445 | ||
446 | #if CONFIG_WAITQ_STATS | |
447 | table->nslabs = 1; | |
448 | table->nallocs = 0; | |
449 | table->nreallocs = 0; | |
450 | table->npreposts = 0; | |
451 | table->nreservations = 0; | |
452 | table->nreserved_releases = 0; | |
453 | ||
454 | table->max_used = 0; | |
455 | table->avg_used = 0; | |
456 | table->max_reservations = 0; | |
457 | table->avg_reservations = 0; | |
458 | #endif | |
459 | } | |
460 | ||
461 | /** | |
462 | * grow a waitq table by adding another 'slab' of table elements | |
463 | * | |
464 | * Conditions: | |
465 | * table mutex is unlocked | |
466 | * calling thread can block | |
467 | */ | |
468 | static void wq_table_grow(struct wq_table *table, uint32_t min_free) | |
469 | { | |
470 | struct wqt_elem *slab, **slot; | |
471 | struct wqt_elem *e = NULL, *first_new_elem, *last_new_elem; | |
472 | struct wq_id free_id; | |
473 | uint32_t free_elem; | |
474 | ||
475 | assert(get_preemption_level() == 0); | |
476 | assert(table && table->slab_zone); | |
477 | ||
478 | lck_mtx_lock(&table->lock); | |
479 | ||
480 | free_elem = table->nelem - table->used_elem; | |
481 | ||
482 | /* | |
483 | * If the caller just wanted to ensure a minimum number of elements, | |
484 | * do that (and don't just blindly grow the table). Also, don't grow | |
485 | * the table unnecessarily - we could have been beaten by a higher | |
486 | * priority thread who acquired the lock and grew the table before we | |
487 | * got here. | |
488 | */ | |
489 | if (free_elem > min_free) { | |
490 | lck_mtx_unlock(&table->lock); | |
491 | return; | |
492 | } | |
493 | ||
494 | /* we are now committed to table growth */ | |
495 | wqdbg_v("BEGIN"); | |
496 | ||
497 | if (table->next_free_slab == NULL) { | |
498 | /* | |
499 | * before we panic, check one more time to see if any other | |
500 | * threads have free'd from space in the table. | |
501 | */ | |
502 | if ((table->nelem - table->used_elem) > 0) { | |
503 | /* there's at least 1 free element: don't panic yet */ | |
504 | lck_mtx_unlock(&table->lock); | |
505 | return; | |
506 | } | |
507 | panic("No more room to grow table: %p (nelem: %d, used: %d)", | |
508 | table, table->nelem, table->used_elem); | |
509 | } | |
510 | slot = table->next_free_slab; | |
511 | table->next_free_slab++; | |
512 | if ((uintptr_t)table->next_free_slab >= (uintptr_t)table->table + PAGE_SIZE) | |
513 | table->next_free_slab = NULL; | |
514 | ||
515 | assert(*slot == NULL); | |
516 | ||
517 | /* allocate another slab */ | |
518 | slab = (struct wqt_elem *)zalloc(table->slab_zone); | |
519 | if (slab == NULL) | |
520 | panic("Can't allocate a %s table (%p) slab from zone:%p", | |
521 | table->slab_zone->zone_name, table, table->slab_zone); | |
522 | ||
523 | memset(slab, 0, table->slab_sz); | |
524 | ||
525 | /* put the new elements into a freelist */ | |
526 | wqdbg_v(" init %d new links...", table->slab_elem); | |
527 | for (unsigned l = 0; l < table->slab_elem; l++) { | |
528 | uint32_t idx = l + table->nelem; | |
529 | if (idx >= (WQT_IDX_MAX - 1)) | |
530 | break; /* the last element of the last slab */ | |
531 | e = wqt_elem_ofst_slab(slab, table->slab_msk, l * table->elem_sz); | |
532 | e->wqt_id.idx = idx; | |
533 | e->wqt_next_idx = idx + 1; | |
534 | } | |
535 | last_new_elem = e; | |
536 | assert(last_new_elem != NULL); | |
537 | ||
538 | first_new_elem = wqt_elem_ofst_slab(slab, table->slab_msk, 0); | |
539 | ||
540 | /* update table book keeping, and atomically swap the freelist head */ | |
541 | *slot = slab; | |
542 | if (table->nelem + table->slab_elem >= WQT_IDX_MAX) | |
543 | table->nelem = WQT_IDX_MAX - 1; | |
544 | else | |
545 | table->nelem += table->slab_elem; | |
546 | ||
547 | #if CONFIG_WAITQ_STATS | |
548 | table->nslabs += 1; | |
549 | #endif | |
550 | ||
551 | /* | |
552 | * The atomic swap of the free list head marks the end of table | |
553 | * growth. Incoming requests may now use the newly allocated slab | |
554 | * of table elements | |
555 | */ | |
556 | free_id = table->free_list; | |
557 | /* connect the existing free list to the end of the new free list */ | |
558 | last_new_elem->wqt_next_idx = free_id.idx; | |
559 | while (OSCompareAndSwap64(free_id.id, first_new_elem->wqt_id.id, | |
560 | &table->free_list.id) == FALSE) { | |
561 | OSMemoryBarrier(); | |
562 | free_id = table->free_list; | |
563 | last_new_elem->wqt_next_idx = free_id.idx; | |
564 | } | |
565 | OSMemoryBarrier(); | |
566 | ||
567 | lck_mtx_unlock(&table->lock); | |
568 | ||
569 | return; | |
570 | } | |
571 | ||
572 | static __attribute__((noinline)) | |
573 | struct wqt_elem *wq_table_alloc_elem(struct wq_table *table, int type, int nelem) | |
574 | { | |
575 | int nspins = 0, ntries = 0, nalloc = 0; | |
576 | uint32_t table_size; | |
577 | struct wqt_elem *elem = NULL; | |
578 | struct wq_id free_id, next_id; | |
579 | ||
580 | static const int max_retries = 500; | |
581 | ||
582 | if (type != WQT_ELEM && type != WQT_LINK && type != WQT_RESERVED) | |
583 | panic("wq_table_aloc of invalid elem type:%d from table @%p", | |
584 | type, table); | |
585 | ||
586 | assert(nelem > 0); | |
587 | elem = NULL; | |
588 | ||
589 | try_again: | |
590 | if (ntries++ > max_retries) { | |
591 | struct wqt_elem *tmp; | |
592 | if (table->used_elem + nelem >= table_size) | |
593 | panic("No more room to grow table: 0x%p size:%d, used:%d, requested elem:%d", | |
594 | table, table_size, table->used_elem, nelem); | |
595 | if (nelem == 1) | |
596 | panic("Too many alloc retries: %d, table:%p, type:%d, nelem:%d", | |
597 | ntries, table, type, nelem); | |
598 | /* don't panic: try allocating one-at-a-time */ | |
599 | while (nelem > 0) { | |
600 | tmp = wq_table_alloc_elem(table, type, 1); | |
601 | if (elem) | |
602 | wqt_elem_list_link(table, tmp, elem); | |
603 | elem = tmp; | |
604 | --nelem; | |
605 | } | |
606 | assert(elem != NULL); | |
607 | return elem; | |
608 | } | |
609 | ||
610 | nalloc = 0; | |
611 | table_size = table->nelem; | |
612 | ||
613 | if (table->used_elem + nelem >= table_size) { | |
614 | if (get_preemption_level() != 0) { | |
615 | #if CONFIG_WAITQ_STATS | |
616 | table->nspins += 1; | |
617 | #endif | |
618 | /* | |
619 | * We may have just raced with table growth: check | |
620 | * again to make sure there really isn't any space. | |
621 | */ | |
622 | if (++nspins > 4) | |
623 | panic("Can't grow table %p with preemption" | |
624 | " disabled!", table); | |
625 | delay(1); | |
626 | goto try_again; | |
627 | } | |
628 | wq_table_grow(table, nelem); | |
629 | goto try_again; | |
630 | } | |
631 | ||
632 | /* read this value only once before the CAS */ | |
633 | free_id = table->free_list; | |
634 | if (free_id.idx >= table_size) | |
635 | goto try_again; | |
636 | ||
637 | /* | |
638 | * Find the item on the free list which will become the new free list | |
639 | * head, but be careful not to modify any memory (read only)! Other | |
640 | * threads can alter table state at any time up until the CAS. We | |
641 | * don't modify any memory until we've successfully swapped out the | |
642 | * free list head with the one we've investigated. | |
643 | */ | |
644 | for (struct wqt_elem *next_elem = wqt_elem_idx(table, free_id.idx); | |
645 | nalloc < nelem; | |
646 | nalloc++) { | |
647 | elem = next_elem; | |
648 | next_id.generation = 0; | |
649 | next_id.idx = next_elem->wqt_next_idx; | |
650 | if (next_id.idx < table->nelem) { | |
651 | next_elem = wqt_elem_idx(table, next_id.idx); | |
652 | next_id.id = next_elem->wqt_id.id; | |
653 | } else { | |
654 | goto try_again; | |
655 | } | |
656 | } | |
657 | /* 'elem' points to the last element being allocated */ | |
658 | ||
659 | if (OSCompareAndSwap64(free_id.id, next_id.id, | |
660 | &table->free_list.id) == FALSE) | |
661 | goto try_again; | |
662 | ||
663 | /* load barrier */ | |
664 | OSMemoryBarrier(); | |
665 | ||
666 | /* | |
667 | * After the CAS, we know that we own free_id, and it points to a | |
668 | * valid table entry (checked above). Grab the table pointer and | |
669 | * reset some values. | |
670 | */ | |
671 | OSAddAtomic(nelem, &table->used_elem); | |
672 | ||
673 | /* end the list of allocated elements */ | |
674 | elem->wqt_next_idx = WQT_IDX_MAX; | |
675 | /* reset 'elem' to point to the first allocated element */ | |
676 | elem = wqt_elem_idx(table, free_id.idx); | |
677 | ||
678 | /* | |
679 | * Update the generation count, and return the element(s) | |
680 | * with a single reference (and no valid bit). If the | |
681 | * caller immediately calls _put() on any element, then | |
682 | * it will be released back to the free list. If the caller | |
683 | * subsequently marks the element as valid, then the put | |
684 | * will simply drop the reference. | |
685 | */ | |
686 | for (struct wqt_elem *tmp = elem; ; ) { | |
687 | assert(!wqt_bits_valid(tmp->wqt_bits) && | |
688 | (wqt_bits_refcnt(tmp->wqt_bits) == 0)); | |
689 | --nalloc; | |
690 | tmp->wqt_id.generation += 1; | |
691 | tmp->wqt_bits = 1; | |
692 | wqt_elem_set_type(tmp, type); | |
693 | if (tmp->wqt_next_idx == WQT_IDX_MAX) | |
694 | break; | |
695 | assert(tmp->wqt_next_idx != WQT_IDX_MAX); | |
696 | tmp = wqt_elem_idx(table, tmp->wqt_next_idx); | |
697 | } | |
698 | assert(nalloc == 0); | |
699 | ||
700 | #if CONFIG_WAITQ_STATS | |
701 | uint64_t nreservations; | |
702 | table->nallocs += nelem; | |
703 | if (type == WQT_RESERVED) | |
704 | OSIncrementAtomic64(&table->nreservations); | |
705 | nreservations = table->nreservations; | |
706 | if (table->used_elem > table->max_used) | |
707 | table->max_used = table->used_elem; | |
708 | if (nreservations > table->max_reservations) | |
709 | table->max_reservations = nreservations; | |
710 | table->avg_used = (table->avg_used + table->used_elem) / 2; | |
711 | table->avg_reservations = (table->avg_reservations + nreservations) / 2; | |
712 | #endif | |
713 | ||
714 | return elem; | |
715 | } | |
716 | ||
717 | static void wq_table_realloc_elem(struct wq_table *table, struct wqt_elem *elem, int type) | |
718 | { | |
719 | (void)table; | |
720 | assert(wqt_elem_in_range(elem, table) && | |
721 | !wqt_bits_valid(elem->wqt_bits)); | |
722 | ||
723 | #if CONFIG_WAITQ_STATS | |
724 | table->nreallocs += 1; | |
725 | if (wqt_bits_type(elem->wqt_bits) == WQT_RESERVED && type != WQT_RESERVED) { | |
726 | /* | |
727 | * This isn't under any lock, so we'll clamp it. | |
728 | * the stats are meant to be informative, not perfectly | |
729 | * accurate | |
730 | */ | |
731 | OSDecrementAtomic64(&table->nreservations); | |
732 | } | |
733 | table->avg_reservations = (table->avg_reservations + table->nreservations) / 2; | |
734 | #endif | |
735 | ||
736 | /* | |
737 | * Return the same element with a new generation count, and a | |
738 | * (potentially) new type. Don't touch the refcount: the caller | |
739 | * is responsible for getting that (and the valid bit) correct. | |
740 | */ | |
741 | elem->wqt_id.generation += 1; | |
742 | elem->wqt_next_idx = WQT_IDX_MAX; | |
743 | wqt_elem_set_type(elem, type); | |
744 | ||
745 | return; | |
746 | } | |
747 | ||
748 | static void wq_table_free_elem(struct wq_table *table, struct wqt_elem *elem) | |
749 | { | |
750 | struct wq_id next_id; | |
751 | ||
752 | assert(wqt_elem_in_range(elem, table) && | |
753 | !wqt_bits_valid(elem->wqt_bits) && | |
754 | (wqt_bits_refcnt(elem->wqt_bits) == 0)); | |
755 | ||
756 | OSDecrementAtomic(&table->used_elem); | |
757 | ||
758 | #if CONFIG_WAITQ_STATS | |
759 | table->avg_used = (table->avg_used + table->used_elem) / 2; | |
760 | if (wqt_bits_type(elem->wqt_bits) == WQT_RESERVED) | |
761 | OSDecrementAtomic64(&table->nreservations); | |
762 | table->avg_reservations = (table->avg_reservations + table->nreservations) / 2; | |
763 | #endif | |
764 | ||
765 | elem->wqt_bits = 0; | |
766 | ||
767 | if (table->poison) | |
768 | (table->poison)(table, elem); | |
769 | ||
770 | again: | |
771 | next_id = table->free_list; | |
772 | if (next_id.idx >= table->nelem) | |
773 | elem->wqt_next_idx = WQT_IDX_MAX; | |
774 | else | |
775 | elem->wqt_next_idx = next_id.idx; | |
776 | ||
777 | /* store barrier */ | |
778 | OSMemoryBarrier(); | |
779 | if (OSCompareAndSwap64(next_id.id, elem->wqt_id.id, | |
780 | &table->free_list.id) == FALSE) | |
781 | goto again; | |
782 | } | |
783 | ||
784 | /* get a reference to a table element identified by 'id' */ | |
785 | static struct wqt_elem *wq_table_get_elem(struct wq_table *table, uint64_t id) | |
786 | { | |
787 | struct wqt_elem *elem; | |
788 | uint32_t idx, bits, new_bits; | |
789 | ||
790 | /* | |
791 | * Here we have a reference to the table which is guaranteed to remain | |
792 | * valid until we drop the reference | |
793 | */ | |
794 | ||
795 | idx = ((struct wq_id *)&id)->idx; | |
796 | ||
797 | if (idx >= table->nelem) | |
798 | panic("id:0x%llx : idx:%d > %d", id, idx, table->nelem); | |
799 | ||
800 | elem = wqt_elem_idx(table, idx); | |
801 | ||
802 | /* verify the validity by taking a reference on the table object */ | |
803 | bits = elem->wqt_bits; | |
804 | if (!wqt_bits_valid(bits)) | |
805 | return NULL; | |
806 | ||
807 | /* | |
808 | * do a pre-verify on the element ID to potentially | |
809 | * avoid 2 compare-and-swaps | |
810 | */ | |
811 | if (elem->wqt_id.id != id) | |
812 | return NULL; | |
813 | ||
814 | new_bits = bits + 1; | |
815 | ||
816 | /* check for overflow */ | |
817 | assert(wqt_bits_refcnt(new_bits) > 0); | |
818 | ||
819 | while (OSCompareAndSwap(bits, new_bits, &elem->wqt_bits) == FALSE) { | |
820 | /* | |
821 | * either the element became invalid, | |
822 | * or someone else grabbed/removed a reference. | |
823 | */ | |
824 | bits = elem->wqt_bits; | |
825 | if (!wqt_bits_valid(bits)) { | |
826 | /* don't return invalid elements */ | |
827 | return NULL; | |
828 | } | |
829 | new_bits = bits + 1; | |
830 | assert(wqt_bits_refcnt(new_bits) > 0); | |
831 | } | |
832 | ||
833 | /* load barrier */ | |
834 | OSMemoryBarrier(); | |
835 | ||
836 | /* check to see that our reference is to the same generation! */ | |
837 | if (elem->wqt_id.id != id) { | |
838 | /* | |
839 | wqdbg("ID:0x%llx table generation (%d) != %d", | |
840 | id, elem->wqt_id.generation, | |
841 | ((struct wq_id *)&id)->generation); | |
842 | */ | |
843 | wq_table_put_elem(table, elem); | |
844 | return NULL; | |
845 | } | |
846 | ||
847 | /* We now have a reference on a valid object */ | |
848 | return elem; | |
849 | } | |
850 | ||
851 | /* release a ref to table element - puts it back on free list as appropriate */ | |
852 | static void wq_table_put_elem(struct wq_table *table, struct wqt_elem *elem) | |
853 | { | |
854 | uint32_t bits, new_bits; | |
855 | ||
856 | assert(wqt_elem_in_range(elem, table)); | |
857 | ||
858 | bits = elem->wqt_bits; | |
859 | new_bits = bits - 1; | |
860 | ||
861 | /* check for underflow */ | |
862 | assert(wqt_bits_refcnt(new_bits) < WQT_BITS_REFCNT_MASK); | |
863 | ||
864 | while (OSCompareAndSwap(bits, new_bits, &elem->wqt_bits) == FALSE) { | |
865 | bits = elem->wqt_bits; | |
866 | new_bits = bits - 1; | |
867 | /* catch underflow */ | |
868 | assert(wqt_bits_refcnt(new_bits) < WQT_BITS_REFCNT_MASK); | |
869 | } | |
870 | ||
871 | /* load barrier */ | |
872 | OSMemoryBarrier(); | |
873 | ||
874 | /* | |
875 | * if this was the last reference, and it was marked as invalid, | |
876 | * then we can add this link object back to the free list | |
877 | */ | |
878 | if (!wqt_bits_valid(new_bits) && (wqt_bits_refcnt(new_bits) == 0)) | |
879 | wq_table_free_elem(table, elem); | |
880 | ||
881 | return; | |
882 | } | |
883 | ||
884 | ||
885 | /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - | |
886 | * | |
887 | * API: wqt_elem_list_... | |
888 | * | |
889 | * Reuse the free list linkage member, 'wqt_next_idx' of a table element | |
890 | * in a slightly more generic singly-linked list. All members of this | |
891 | * list have been allocated from a table, but have not been made valid. | |
892 | * | |
893 | * - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -*/ | |
894 | ||
895 | /* link parent->child */ | |
896 | static int wqt_elem_list_link(struct wq_table *table, struct wqt_elem *parent, struct wqt_elem *child) | |
897 | { | |
898 | int nelem = 1; | |
899 | ||
900 | assert(wqt_elem_in_range(parent, table)); | |
901 | ||
902 | /* find the end of the parent's list */ | |
903 | while (parent->wqt_next_idx != WQT_IDX_MAX) { | |
904 | assert(parent->wqt_next_idx < table->nelem); | |
905 | parent = wqt_elem_idx(table, parent->wqt_next_idx); | |
906 | nelem++; | |
907 | } | |
908 | ||
909 | if (child) { | |
910 | assert(wqt_elem_in_range(child, table)); | |
911 | parent->wqt_next_idx = child->wqt_id.idx; | |
912 | } | |
913 | ||
914 | return nelem; | |
915 | } | |
916 | ||
917 | static struct wqt_elem *wqt_elem_list_next(struct wq_table *table, struct wqt_elem *head) | |
918 | { | |
919 | struct wqt_elem *elem; | |
920 | ||
921 | if (!head) | |
922 | return NULL; | |
923 | if (head->wqt_next_idx >= table->nelem) | |
924 | return NULL; | |
925 | ||
926 | elem = wqt_elem_idx(table, head->wqt_next_idx); | |
927 | assert(wqt_elem_in_range(elem, table)); | |
928 | ||
929 | return elem; | |
930 | } | |
931 | ||
932 | /* | |
933 | * Obtain a pointer to the first element of a list. Don't take an extra | |
934 | * reference on the object - the list implicitly holds that reference. | |
935 | * | |
936 | * This function is used to convert the head of a singly-linked list | |
937 | * to a real wqt_elem object. | |
938 | */ | |
939 | static struct wqt_elem *wqt_elem_list_first(struct wq_table *table, uint64_t id) | |
940 | { | |
941 | uint32_t idx; | |
942 | struct wqt_elem *elem = NULL; | |
943 | ||
944 | if (id == 0) | |
945 | return NULL; | |
946 | ||
947 | idx = ((struct wq_id *)&id)->idx; | |
948 | ||
949 | if (idx > table->nelem) | |
950 | panic("Invalid element for id:0x%llx", id); | |
951 | elem = wqt_elem_idx(table, idx); | |
952 | ||
953 | /* invalid element: reserved ID was probably already reallocated */ | |
954 | if (elem->wqt_id.id != id) | |
955 | return NULL; | |
956 | ||
957 | /* the returned element should _not_ be marked valid! */ | |
958 | if (wqt_bits_valid(elem->wqt_bits) || | |
959 | wqt_bits_type(elem->wqt_bits) != WQT_RESERVED || | |
960 | wqt_bits_refcnt(elem->wqt_bits) != 1) { | |
961 | panic("Valid/unreserved element %p (0x%x) in reserved list", | |
962 | elem, elem->wqt_bits); | |
963 | } | |
964 | ||
965 | return elem; | |
966 | } | |
967 | ||
968 | static void wqt_elem_reset_next(struct wq_table *table, struct wqt_elem *wqp) | |
969 | { | |
970 | (void)table; | |
971 | ||
972 | if (!wqp) | |
973 | return; | |
974 | assert(wqt_elem_in_range(wqp, table)); | |
975 | ||
976 | wqp->wqt_next_idx = WQT_IDX_MAX; | |
977 | } | |
978 | ||
979 | /* | |
980 | * Pop an item off the list. | |
981 | * New list head returned in *id, caller responsible for reference on returned | |
982 | * object. We do a realloc here to reset the type of the object, but still | |
983 | * leave it invalid. | |
984 | */ | |
985 | static struct wqt_elem *wqt_elem_list_pop(struct wq_table *table, uint64_t *id, int type) | |
986 | { | |
987 | struct wqt_elem *first, *next; | |
988 | ||
989 | if (!id || *id == 0) | |
990 | return NULL; | |
991 | ||
992 | /* pop an item off the reserved stack */ | |
993 | ||
994 | first = wqt_elem_list_first(table, *id); | |
995 | if (!first) { | |
996 | *id = 0; | |
997 | return NULL; | |
998 | } | |
999 | ||
1000 | next = wqt_elem_list_next(table, first); | |
1001 | if (next) | |
1002 | *id = next->wqt_id.id; | |
1003 | else | |
1004 | *id = 0; | |
1005 | ||
1006 | wq_table_realloc_elem(table, first, type); | |
1007 | ||
1008 | return first; | |
1009 | } | |
1010 | ||
1011 | /* | |
1012 | * Free an entire list of linked/reserved elements | |
1013 | */ | |
1014 | static int wqt_elem_list_release(struct wq_table *table, | |
1015 | struct wqt_elem *head, | |
1016 | int __assert_only type) | |
1017 | { | |
1018 | struct wqt_elem *elem; | |
1019 | struct wq_id free_id; | |
1020 | int nelem = 0; | |
1021 | ||
1022 | if (!head) | |
1023 | return 0; | |
1024 | ||
1025 | for (elem = head; ; ) { | |
1026 | assert(wqt_elem_in_range(elem, table)); | |
1027 | assert(!wqt_bits_valid(elem->wqt_bits) && (wqt_bits_refcnt(elem->wqt_bits) == 1)); | |
1028 | assert(wqt_bits_type(elem->wqt_bits) == type); | |
1029 | ||
1030 | nelem++; | |
1031 | elem->wqt_bits = 0; | |
1032 | if (table->poison) | |
1033 | (table->poison)(table, elem); | |
1034 | ||
1035 | if (elem->wqt_next_idx == WQT_IDX_MAX) | |
1036 | break; | |
1037 | assert(elem->wqt_next_idx < table->nelem); | |
1038 | elem = wqt_elem_idx(table, elem->wqt_next_idx); | |
1039 | } | |
1040 | ||
1041 | /* | |
1042 | * 'elem' now points to the end of our list, and 'head' points to the | |
1043 | * beginning. We want to atomically swap the free list pointer with | |
1044 | * the 'head' and ensure that 'elem' points to the previous free list | |
1045 | * head. | |
1046 | */ | |
1047 | ||
1048 | again: | |
1049 | free_id = table->free_list; | |
1050 | if (free_id.idx >= table->nelem) | |
1051 | elem->wqt_next_idx = WQT_IDX_MAX; | |
1052 | else | |
1053 | elem->wqt_next_idx = free_id.idx; | |
1054 | ||
1055 | /* store barrier */ | |
1056 | OSMemoryBarrier(); | |
1057 | if (OSCompareAndSwap64(free_id.id, head->wqt_id.id, | |
1058 | &table->free_list.id) == FALSE) | |
1059 | goto again; | |
1060 | ||
1061 | OSAddAtomic(-nelem, &table->used_elem); | |
1062 | return nelem; | |
1063 | } | |
1064 | ||
1065 | ||
1066 | /* ---------------------------------------------------------------------- | |
1067 | * | |
1068 | * SetID Link Table Implementation | |
1069 | * | |
1070 | * ---------------------------------------------------------------------- */ | |
1071 | static struct wq_table g_linktable; | |
1072 | ||
1073 | enum setid_link_type { | |
1074 | SLT_ALL = -1, | |
1075 | SLT_FREE = WQT_FREE, | |
1076 | SLT_WQS = WQT_ELEM, | |
1077 | SLT_LINK = WQT_LINK, | |
1078 | }; | |
1079 | ||
1080 | struct setid_link { | |
1081 | struct wqt_elem wqte; | |
1082 | ||
1083 | union { | |
1084 | /* wqt_type == SLT_WQS (WQT_ELEM) */ | |
1085 | struct { | |
1086 | struct waitq_set *sl_set; | |
1087 | /* uint64_t sl_prepost_id; */ | |
1088 | } sl_wqs; | |
1089 | ||
1090 | /* wqt_type == SLT_LINK (WQT_LINK) */ | |
1091 | struct { | |
1092 | uint64_t sl_left_setid; | |
1093 | uint64_t sl_right_setid; | |
1094 | } sl_link; | |
1095 | }; | |
1096 | #ifdef CONFIG_WAITQ_LINK_STATS | |
1097 | thread_t sl_alloc_th; | |
1098 | task_t sl_alloc_task; | |
1099 | uintptr_t sl_alloc_bt[NWAITQ_BTFRAMES]; | |
1100 | uint64_t sl_alloc_ts; | |
1101 | uintptr_t sl_invalidate_bt[NWAITQ_BTFRAMES]; | |
1102 | uint64_t sl_invalidate_ts; | |
1103 | uintptr_t sl_mkvalid_bt[NWAITQ_BTFRAMES]; | |
1104 | uint64_t sl_mkvalid_ts; | |
1105 | uint64_t sl_free_ts; | |
1106 | #endif | |
1107 | }; | |
1108 | #if !defined(CONFIG_WAITQ_LINK_STATS) | |
1109 | _Static_assert((sizeof(struct setid_link) & (sizeof(struct setid_link) - 1)) == 0, | |
1110 | "setid_link struct must be a power of two!"); | |
1111 | #endif | |
1112 | ||
1113 | #define sl_refcnt(link) \ | |
1114 | (wqt_bits_refcnt((link)->wqte.wqt_bits)) | |
1115 | ||
1116 | #define sl_type(link) \ | |
1117 | (wqt_bits_type((link)->wqte.wqt_bits)) | |
1118 | ||
1119 | #define sl_set_valid(link) \ | |
1120 | do { \ | |
1121 | wqt_elem_mkvalid(&(link)->wqte); \ | |
1122 | lt_do_mkvalid_stats(&(link)->wqte); \ | |
1123 | } while (0) | |
1124 | ||
1125 | #define sl_is_valid(link) \ | |
1126 | wqt_bits_valid((link)->wqte.wqt_bits) | |
1127 | ||
1128 | #define sl_set_id wqte.wqt_id | |
1129 | ||
1130 | #define SLT_WQS_POISON ((void *)(0xf00df00d)) | |
1131 | #define SLT_LINK_POISON (0x0bad0badffffffffull) | |
1132 | ||
1133 | static void lt_poison(struct wq_table *table, struct wqt_elem *elem) | |
1134 | { | |
1135 | struct setid_link *sl_link = (struct setid_link *)elem; | |
1136 | (void)table; | |
1137 | ||
1138 | switch (sl_type(sl_link)) { | |
1139 | case SLT_WQS: | |
1140 | sl_link->sl_wqs.sl_set = SLT_WQS_POISON; | |
1141 | break; | |
1142 | case SLT_LINK: | |
1143 | sl_link->sl_link.sl_left_setid = SLT_LINK_POISON; | |
1144 | sl_link->sl_link.sl_right_setid = SLT_LINK_POISON; | |
1145 | break; | |
1146 | default: | |
1147 | break; | |
1148 | } | |
1149 | #ifdef CONFIG_WAITQ_LINK_STATS | |
1150 | memset(sl_link->sl_alloc_bt, 0, sizeof(sl_link->sl_alloc_bt)); | |
1151 | sl_link->sl_alloc_ts = 0; | |
1152 | memset(sl_link->sl_mkvalid_bt, 0, sizeof(sl_link->sl_mkvalid_bt)); | |
1153 | sl_link->sl_mkvalid_ts = 0; | |
1154 | ||
1155 | sl_link->sl_alloc_th = THREAD_NULL; | |
1156 | /* leave the sl_alloc_task in place for debugging */ | |
1157 | ||
1158 | sl_link->sl_free_ts = mach_absolute_time(); | |
1159 | #endif | |
1160 | } | |
1161 | ||
1162 | #ifdef CONFIG_WAITQ_LINK_STATS | |
1163 | static __inline__ void lt_do_alloc_stats(struct wqt_elem *elem) | |
1164 | { | |
1165 | if (elem) { | |
1166 | struct setid_link *link = (struct setid_link *)elem; | |
1167 | memset(link->sl_alloc_bt, 0, sizeof(link->sl_alloc_bt)); | |
1168 | waitq_grab_backtrace(link->sl_alloc_bt, 0); | |
1169 | link->sl_alloc_th = current_thread(); | |
1170 | link->sl_alloc_task = current_task(); | |
1171 | ||
1172 | assert(link->sl_alloc_ts == 0); | |
1173 | link->sl_alloc_ts = mach_absolute_time(); | |
1174 | ||
1175 | memset(link->sl_invalidate_bt, 0, sizeof(link->sl_invalidate_bt)); | |
1176 | link->sl_invalidate_ts = 0; | |
1177 | } | |
1178 | } | |
1179 | ||
1180 | static __inline__ void lt_do_invalidate_stats(struct wqt_elem *elem) | |
1181 | { | |
1182 | struct setid_link *link = (struct setid_link *)elem; | |
1183 | ||
1184 | if (!elem) | |
1185 | return; | |
1186 | ||
1187 | assert(link->sl_mkvalid_ts > 0); | |
1188 | ||
1189 | memset(link->sl_invalidate_bt, 0, sizeof(link->sl_invalidate_bt)); | |
1190 | link->sl_invalidate_ts = mach_absolute_time(); | |
1191 | waitq_grab_backtrace(link->sl_invalidate_bt, 0); | |
1192 | } | |
1193 | ||
1194 | static __inline__ void lt_do_mkvalid_stats(struct wqt_elem *elem) | |
1195 | { | |
1196 | struct setid_link *link = (struct setid_link *)elem; | |
1197 | ||
1198 | if (!elem) | |
1199 | return; | |
1200 | ||
1201 | memset(link->sl_mkvalid_bt, 0, sizeof(link->sl_mkvalid_bt)); | |
1202 | link->sl_mkvalid_ts = mach_absolute_time(); | |
1203 | waitq_grab_backtrace(link->sl_mkvalid_bt, 0); | |
1204 | } | |
1205 | #else | |
1206 | #define lt_do_alloc_stats(e) | |
1207 | #define lt_do_invalidate_stats(e) | |
1208 | #define lt_do_mkvalid_stats(e) | |
1209 | #endif /* CONFIG_WAITQ_LINK_STATS */ | |
1210 | ||
1211 | static void lt_init(void) | |
1212 | { | |
1213 | uint32_t tablesz = 0, max_links = 0; | |
1214 | ||
1215 | if (PE_parse_boot_argn("wql_tsize", &tablesz, sizeof(tablesz)) != TRUE) | |
1216 | tablesz = (uint32_t)g_wqt_max_tbl_size; | |
1217 | ||
1218 | tablesz = P2ROUNDUP(tablesz, PAGE_SIZE); | |
1219 | max_links = tablesz / sizeof(struct setid_link); | |
1220 | assert(max_links > 0 && tablesz > 0); | |
1221 | ||
1222 | /* we have a restricted index range */ | |
1223 | if (max_links > (WQT_IDX_MAX + 1)) | |
1224 | max_links = WQT_IDX_MAX + 1; | |
1225 | ||
1226 | wqinfo("init linktable with max:%d elements (%d bytes)", | |
1227 | max_links, tablesz); | |
1228 | wq_table_init(&g_linktable, "wqslab.links", max_links, | |
1229 | sizeof(struct setid_link), lt_poison); | |
1230 | } | |
1231 | ||
1232 | static void lt_ensure_free_space(void) | |
1233 | { | |
1234 | if (g_linktable.nelem - g_linktable.used_elem < g_min_free_table_elem) { | |
1235 | /* | |
1236 | * we don't hold locks on these values, so check for underflow | |
1237 | */ | |
1238 | if (g_linktable.used_elem <= g_linktable.nelem) { | |
1239 | wqdbg_v("Forcing table growth: nelem=%d, used=%d, min_free=%d", | |
1240 | g_linktable.nelem, g_linktable.used_elem, | |
1241 | g_min_free_table_elem); | |
1242 | wq_table_grow(&g_linktable, g_min_free_table_elem); | |
1243 | } | |
1244 | } | |
1245 | } | |
1246 | ||
1247 | static struct setid_link *lt_alloc_link(int type) | |
1248 | { | |
1249 | struct wqt_elem *elem; | |
1250 | ||
1251 | elem = wq_table_alloc_elem(&g_linktable, type, 1); | |
1252 | lt_do_alloc_stats(elem); | |
1253 | return (struct setid_link *)elem; | |
1254 | } | |
1255 | ||
1256 | static void lt_realloc_link(struct setid_link *link, int type) | |
1257 | { | |
1258 | wq_table_realloc_elem(&g_linktable, &link->wqte, type); | |
1259 | #ifdef CONFIG_WAITQ_LINK_STATS | |
1260 | memset(link->sl_alloc_bt, 0, sizeof(link->sl_alloc_bt)); | |
1261 | link->sl_alloc_ts = 0; | |
1262 | lt_do_alloc_stats(&link->wqte); | |
1263 | ||
1264 | memset(link->sl_invalidate_bt, 0, sizeof(link->sl_invalidate_bt)); | |
1265 | link->sl_invalidate_ts = 0; | |
1266 | #endif | |
1267 | } | |
1268 | ||
1269 | static void lt_invalidate(struct setid_link *link) | |
1270 | { | |
1271 | wqt_elem_invalidate(&link->wqte); | |
1272 | lt_do_invalidate_stats(&link->wqte); | |
1273 | } | |
1274 | ||
1275 | static struct setid_link *lt_get_link(uint64_t setid) | |
1276 | { | |
1277 | struct wqt_elem *elem; | |
1278 | ||
1279 | elem = wq_table_get_elem(&g_linktable, setid); | |
1280 | return (struct setid_link *)elem; | |
1281 | } | |
1282 | ||
1283 | static void lt_put_link(struct setid_link *link) | |
1284 | { | |
1285 | if (!link) | |
1286 | return; | |
1287 | wq_table_put_elem(&g_linktable, (struct wqt_elem *)link); | |
1288 | } | |
1289 | ||
1290 | static struct setid_link *lt_get_reserved(uint64_t setid, int type) | |
1291 | { | |
1292 | struct wqt_elem *elem; | |
1293 | ||
1294 | elem = wqt_elem_list_first(&g_linktable, setid); | |
1295 | if (!elem) | |
1296 | return NULL; | |
1297 | wq_table_realloc_elem(&g_linktable, elem, type); | |
1298 | return (struct setid_link *)elem; | |
1299 | } | |
1300 | ||
1301 | ||
1302 | static inline int waitq_maybe_remove_link(struct waitq *waitq, | |
1303 | uint64_t setid, | |
1304 | struct setid_link *parent, | |
1305 | struct setid_link *left, | |
1306 | struct setid_link *right); | |
1307 | ||
1308 | enum { | |
1309 | LINK_WALK_ONE_LEVEL = 0, | |
1310 | LINK_WALK_FULL_DAG = 1, | |
1311 | LINK_WALK_FULL_DAG_UNLOCKED = 2, | |
1312 | }; | |
1313 | ||
1314 | typedef int (*lt_callback_func)(struct waitq *waitq, void *ctx, | |
1315 | struct setid_link *link); | |
1316 | ||
1317 | /** | |
1318 | * walk all table elements (of type 'link_type') pointed to by 'setid' | |
1319 | * | |
1320 | * Conditions: | |
1321 | * waitq is locked (or NULL) | |
1322 | * 'setid' is managed by 'waitq' | |
1323 | * this could be direct (waitq->waitq_set_id == setid) | |
1324 | * OR indirect (setid is the left/right ID in a LINK chain, | |
1325 | * whose root is waitq->waitq_set_id) | |
1326 | * | |
1327 | * Notes: | |
1328 | * This function uses recursion to walk the set of table elements | |
1329 | * pointed to by 'setid'. For each element encountered, 'cb' will be | |
1330 | * called. If non-zero, the return value of this callback function can | |
1331 | * early-out of the table walk. | |
1332 | * | |
1333 | * For each link element encountered, the function takes a reference to | |
1334 | * it. The reference is dropped only after the callback and any recursion | |
1335 | * has completed. | |
1336 | * | |
1337 | * The assumed table/link/tree structure: | |
1338 | * 'setid' | |
1339 | * / \ | |
1340 | * / \ | |
1341 | * L(LINK) R(LINK) | |
1342 | * /\ /\ | |
1343 | * / \ / \ | |
1344 | * / \ Rl(*) Rr(*) | |
1345 | * Ll(*) Lr(*) /\ /\ | |
1346 | * /\ /\ ... ... ... ... | |
1347 | * ... ... ... ... | |
1348 | * \ | |
1349 | * WQS(wqset_q.waitq_setid == Sx) | |
1350 | * [waitq set is a membet of setid, 'Sx') | |
1351 | * | |
1352 | * 'Sx' | |
1353 | * / \ | |
1354 | * / \ | |
1355 | * L(LINK) R(LINK) | |
1356 | * /\ /\ | |
1357 | * ... ... ... ... | |
1358 | * | |
1359 | * The basic algorithm is as follows: | |
1360 | * *) take a reference to the table object pointed to by 'setid' | |
1361 | * *) if appropriate, call 'cb' (potentially early-out on non-zero return) | |
1362 | * *) if the link object points to a waitq set, and the walk type | |
1363 | * is 'FULL_DAG' (full directed-acyclic-graph), then try to lock | |
1364 | * the associated waitq set object and recursively walk all sets to | |
1365 | * which that set belongs. This is a DFS of the tree structure. | |
1366 | * *) recurse down the left side of the tree (following the | |
1367 | * 'sl_left_setid' pointer in the link object | |
1368 | * *) recurse down the right side of the tree (following the | |
1369 | * 'sl_right_setid' pointer in the link object | |
1370 | */ | |
1371 | static __attribute__((noinline)) | |
1372 | int walk_setid_links(int walk_type, struct waitq *waitq, | |
1373 | uint64_t setid, int link_type, | |
1374 | void *ctx, lt_callback_func cb) | |
1375 | { | |
1376 | struct setid_link *link; | |
1377 | uint64_t nextid; | |
1378 | int sl_type; | |
1379 | ||
1380 | link = lt_get_link(setid); | |
1381 | ||
1382 | /* invalid link */ | |
1383 | if (!link) | |
1384 | return WQ_ITERATE_CONTINUE; | |
1385 | ||
1386 | setid = nextid = 0; | |
1387 | sl_type = sl_type(link); | |
1388 | if (sl_type == SLT_LINK) { | |
1389 | setid = link->sl_link.sl_left_setid; | |
1390 | nextid = link->sl_link.sl_right_setid; | |
1391 | } | |
1392 | ||
1393 | /* | |
1394 | * Make the callback only on specified link_type (or all links) | |
1395 | * Note that after the callback, the link object may be | |
1396 | * invalid. The only valid thing we can do is put our | |
1397 | * reference to it (which may put it back on the free list) | |
1398 | */ | |
1399 | if (link_type == SLT_ALL || link_type == sl_type) { | |
1400 | /* allow the callback to early-out */ | |
1401 | int ret = cb(waitq, ctx, link); | |
1402 | if (ret != WQ_ITERATE_CONTINUE) { | |
1403 | lt_put_link(link); | |
1404 | return ret; | |
1405 | } | |
1406 | } | |
1407 | ||
1408 | if (sl_type == SLT_WQS && | |
1409 | (walk_type == LINK_WALK_FULL_DAG || | |
1410 | walk_type == LINK_WALK_FULL_DAG_UNLOCKED)) { | |
1411 | /* | |
1412 | * Recurse down any sets to which this wait queue set was | |
1413 | * added. We do this just before we put our reference to | |
1414 | * the link object (which may free it). | |
1415 | */ | |
1416 | struct waitq_set *wqset = link->sl_wqs.sl_set; | |
1417 | int ret = WQ_ITERATE_CONTINUE; | |
1418 | int get_spl = 0; | |
1419 | int should_unlock = 0; | |
1420 | uint64_t wqset_setid = 0; | |
1421 | spl_t set_spl; | |
1422 | ||
1423 | if (waitq_set_is_valid(wqset) && walk_type == LINK_WALK_FULL_DAG) { | |
1424 | if ((!waitq || !waitq_irq_safe(waitq)) && | |
1425 | waitq_irq_safe(&wqset->wqset_q)) { | |
1426 | get_spl = 1; | |
1427 | set_spl = splsched(); | |
1428 | } | |
1429 | waitq_set_lock(wqset); | |
1430 | should_unlock = 1; | |
1431 | } | |
1432 | ||
1433 | /* | |
1434 | * verify the linked waitq set as it could have been | |
1435 | * invalidated before we grabbed the lock! | |
1436 | */ | |
1437 | if (wqset->wqset_id != link->sl_set_id.id) { | |
1438 | /*This is the bottom of the tree: just get out */ | |
1439 | if (should_unlock) { | |
1440 | waitq_set_unlock(wqset); | |
1441 | if (get_spl) | |
1442 | splx(set_spl); | |
1443 | } | |
1444 | lt_put_link(link); | |
1445 | return WQ_ITERATE_CONTINUE; | |
1446 | } | |
1447 | ||
1448 | wqset_setid = wqset->wqset_q.waitq_set_id; | |
1449 | ||
1450 | if (wqset_setid > 0) | |
1451 | ret = walk_setid_links(walk_type, &wqset->wqset_q, | |
1452 | wqset_setid, link_type, ctx, cb); | |
1453 | if (should_unlock) { | |
1454 | waitq_set_unlock(wqset); | |
1455 | if (get_spl) | |
1456 | splx(set_spl); | |
1457 | } | |
1458 | if (ret != WQ_ITERATE_CONTINUE) { | |
1459 | lt_put_link(link); | |
1460 | return ret; | |
1461 | } | |
1462 | } | |
1463 | ||
1464 | lt_put_link(link); | |
1465 | ||
1466 | /* recurse down left side of the tree */ | |
1467 | if (setid) { | |
1468 | int ret = walk_setid_links(walk_type, waitq, setid, link_type, ctx, cb); | |
1469 | if (ret != WQ_ITERATE_CONTINUE) | |
1470 | return ret; | |
1471 | } | |
1472 | ||
1473 | /* recurse down right side of the tree */ | |
1474 | if (nextid) | |
1475 | return walk_setid_links(walk_type, waitq, nextid, link_type, ctx, cb); | |
1476 | ||
1477 | return WQ_ITERATE_CONTINUE; | |
1478 | } | |
1479 | ||
1480 | /* ---------------------------------------------------------------------- | |
1481 | * | |
1482 | * Prepost Link Table Implementation | |
1483 | * | |
1484 | * ---------------------------------------------------------------------- */ | |
1485 | static struct wq_table g_prepost_table; | |
1486 | ||
1487 | enum wq_prepost_type { | |
1488 | WQP_FREE = WQT_FREE, | |
1489 | WQP_WQ = WQT_ELEM, | |
1490 | WQP_POST = WQT_LINK, | |
1491 | }; | |
1492 | ||
1493 | struct wq_prepost { | |
1494 | struct wqt_elem wqte; | |
1495 | ||
1496 | union { | |
1497 | /* wqt_type == WQP_WQ (WQT_ELEM) */ | |
1498 | struct { | |
1499 | struct waitq *wqp_wq_ptr; | |
1500 | } wqp_wq; | |
1501 | /* wqt_type == WQP_POST (WQT_LINK) */ | |
1502 | struct { | |
1503 | uint64_t wqp_next_id; | |
1504 | uint64_t wqp_wq_id; | |
1505 | } wqp_post; | |
1506 | }; | |
1507 | #ifdef CONFIG_WAITQ_PREPOST_STATS | |
1508 | thread_t wqp_alloc_th; | |
1509 | task_t wqp_alloc_task; | |
1510 | uintptr_t wqp_alloc_bt[NWAITQ_BTFRAMES]; | |
1511 | #endif | |
1512 | }; | |
1513 | #if !defined(CONFIG_WAITQ_PREPOST_STATS) | |
1514 | _Static_assert((sizeof(struct wq_prepost) & (sizeof(struct wq_prepost) - 1)) == 0, | |
1515 | "wq_prepost struct must be a power of two!"); | |
1516 | #endif | |
1517 | ||
1518 | #define wqp_refcnt(wqp) \ | |
1519 | (wqt_bits_refcnt((wqp)->wqte.wqt_bits)) | |
1520 | ||
1521 | #define wqp_type(wqp) \ | |
1522 | (wqt_bits_type((wqp)->wqte.wqt_bits)) | |
1523 | ||
1524 | #define wqp_set_valid(wqp) \ | |
1525 | wqt_elem_mkvalid(&(wqp)->wqte) | |
1526 | ||
1527 | #define wqp_is_valid(wqp) \ | |
1528 | wqt_bits_valid((wqp)->wqte.wqt_bits) | |
1529 | ||
1530 | #define wqp_prepostid wqte.wqt_id | |
1531 | ||
1532 | #define WQP_WQ_POISON (0x0bad0badffffffffull) | |
1533 | #define WQP_POST_POISON (0xf00df00df00df00d) | |
1534 | ||
1535 | static void wqp_poison(struct wq_table *table, struct wqt_elem *elem) | |
1536 | { | |
1537 | struct wq_prepost *wqp = (struct wq_prepost *)elem; | |
1538 | (void)table; | |
1539 | ||
1540 | switch (wqp_type(wqp)) { | |
1541 | case WQP_WQ: | |
1542 | break; | |
1543 | case WQP_POST: | |
1544 | wqp->wqp_post.wqp_next_id = WQP_POST_POISON; | |
1545 | wqp->wqp_post.wqp_wq_id = WQP_POST_POISON; | |
1546 | break; | |
1547 | default: | |
1548 | break; | |
1549 | } | |
1550 | } | |
1551 | ||
1552 | #ifdef CONFIG_WAITQ_PREPOST_STATS | |
1553 | static __inline__ void wqp_do_alloc_stats(struct wqt_elem *elem) | |
1554 | { | |
1555 | if (elem) { | |
1556 | struct wq_prepost *wqp = (struct wq_prepost *)elem; | |
1557 | ||
1558 | /* be sure the take stats for _all_ allocated objects */ | |
1559 | for (;;) { | |
1560 | uint32_t next_idx; | |
1561 | ||
1562 | memset(wqp->wqp_alloc_bt, 0, sizeof(wqp->wqp_alloc_bt)); | |
1563 | waitq_grab_backtrace(wqp->wqp_alloc_bt, 4); | |
1564 | wqp->wqp_alloc_th = current_thread(); | |
1565 | wqp->wqp_alloc_task = current_task(); | |
1566 | next_idx = wqp->wqte.wqt_next_idx; | |
1567 | ||
1568 | if (next_idx == WQT_IDX_MAX) | |
1569 | break; | |
1570 | assert(next_idx < g_prepost_table.nelem); | |
1571 | ||
1572 | wqp = (struct wq_prepost *)wqt_elem_idx(&g_prepost_table, | |
1573 | next_idx); | |
1574 | } | |
1575 | } | |
1576 | } | |
1577 | #else | |
1578 | #define wqp_do_alloc_stats(e) | |
1579 | #endif /* CONFIG_WAITQ_LINK_STATS */ | |
1580 | ||
1581 | static void wqp_init(void) | |
1582 | { | |
1583 | uint32_t tablesz = 0, max_wqp = 0; | |
1584 | ||
1585 | if (PE_parse_boot_argn("wqp_tsize", &tablesz, sizeof(tablesz)) != TRUE) | |
1586 | tablesz = (uint32_t)g_wqt_max_tbl_size; | |
1587 | ||
1588 | tablesz = P2ROUNDUP(tablesz, PAGE_SIZE); | |
1589 | max_wqp = tablesz / sizeof(struct wq_prepost); | |
1590 | assert(max_wqp > 0 && tablesz > 0); | |
1591 | ||
1592 | /* we have a restricted index range */ | |
1593 | if (max_wqp > (WQT_IDX_MAX + 1)) | |
1594 | max_wqp = WQT_IDX_MAX + 1; | |
1595 | ||
1596 | wqinfo("init prepost table with max:%d elements (%d bytes)", | |
1597 | max_wqp, tablesz); | |
1598 | wq_table_init(&g_prepost_table, "wqslab.prepost", max_wqp, | |
1599 | sizeof(struct wq_prepost), wqp_poison); | |
1600 | } | |
1601 | ||
1602 | /* | |
1603 | * Refill the per-CPU cache. | |
1604 | */ | |
1605 | static void wq_prepost_refill_cpu_cache(uint32_t nalloc) | |
1606 | { | |
1607 | struct wqt_elem *new_head, *old_head; | |
1608 | struct wqp_cache *cache; | |
1609 | ||
1610 | /* require preemption enabled to allocate elements */ | |
1611 | if (get_preemption_level() != 0) | |
1612 | return; | |
1613 | ||
1614 | new_head = wq_table_alloc_elem(&g_prepost_table, | |
1615 | WQT_RESERVED, nalloc); | |
1616 | if (new_head == NULL) | |
1617 | return; | |
1618 | ||
1619 | disable_preemption(); | |
1620 | cache = &PROCESSOR_DATA(current_processor(), wqp_cache); | |
1621 | cache->avail += nalloc; | |
1622 | if (cache->head == 0 || cache->head == WQT_IDX_MAX) { | |
1623 | cache->head = new_head->wqt_id.id; | |
1624 | goto out; | |
1625 | } | |
1626 | ||
1627 | old_head = wqt_elem_list_first(&g_prepost_table, cache->head); | |
1628 | (void)wqt_elem_list_link(&g_prepost_table, new_head, old_head); | |
1629 | cache->head = new_head->wqt_id.id; | |
1630 | ||
1631 | out: | |
1632 | enable_preemption(); | |
1633 | return; | |
1634 | } | |
1635 | ||
1636 | static void wq_prepost_ensure_free_space(void) | |
1637 | { | |
1638 | uint32_t free_elem; | |
1639 | uint32_t min_free; | |
1640 | struct wqp_cache *cache; | |
1641 | ||
1642 | if (g_min_free_cache == 0) | |
1643 | g_min_free_cache = (WQP_CACHE_MAX * ml_get_max_cpus()); | |
1644 | ||
1645 | /* | |
1646 | * Ensure that we always have a pool of per-CPU prepost elements | |
1647 | */ | |
1648 | disable_preemption(); | |
1649 | cache = &PROCESSOR_DATA(current_processor(), wqp_cache); | |
1650 | free_elem = cache->avail; | |
1651 | enable_preemption(); | |
1652 | ||
1653 | if (free_elem < (WQP_CACHE_MAX / 3)) | |
1654 | wq_prepost_refill_cpu_cache(WQP_CACHE_MAX - free_elem); | |
1655 | ||
1656 | /* | |
1657 | * Now ensure that we have a sufficient amount of free table space | |
1658 | */ | |
1659 | free_elem = g_prepost_table.nelem - g_prepost_table.used_elem; | |
1660 | min_free = g_min_free_table_elem + g_min_free_cache; | |
1661 | if (free_elem < min_free) { | |
1662 | /* | |
1663 | * we don't hold locks on these values, so check for underflow | |
1664 | */ | |
1665 | if (g_prepost_table.used_elem <= g_prepost_table.nelem) { | |
1666 | wqdbg_v("Forcing table growth: nelem=%d, used=%d, min_free=%d+%d", | |
1667 | g_prepost_table.nelem, g_prepost_table.used_elem, | |
1668 | g_min_free_table_elem, g_min_free_cache); | |
1669 | wq_table_grow(&g_prepost_table, min_free); | |
1670 | } | |
1671 | } | |
1672 | } | |
1673 | ||
1674 | static struct wq_prepost *wq_prepost_alloc(int type, int nelem) | |
1675 | { | |
1676 | struct wqt_elem *elem; | |
1677 | struct wq_prepost *wqp; | |
1678 | struct wqp_cache *cache; | |
1679 | ||
1680 | if (type != WQT_RESERVED) | |
1681 | goto do_alloc; | |
1682 | if (nelem == 0) | |
1683 | return NULL; | |
1684 | ||
1685 | /* | |
1686 | * First try to grab the elements from the per-CPU cache if we are | |
1687 | * allocating RESERVED elements | |
1688 | */ | |
1689 | disable_preemption(); | |
1690 | cache = &PROCESSOR_DATA(current_processor(), wqp_cache); | |
1691 | if (nelem <= (int)cache->avail) { | |
1692 | struct wqt_elem *first, *next = NULL; | |
1693 | int nalloc = nelem; | |
1694 | ||
1695 | cache->avail -= nelem; | |
1696 | ||
1697 | /* grab the first element */ | |
1698 | first = wqt_elem_list_first(&g_prepost_table, cache->head); | |
1699 | ||
1700 | /* find the last element and re-adjust the cache head */ | |
1701 | for (elem = first; elem != NULL && nalloc > 0; elem = next) { | |
1702 | next = wqt_elem_list_next(&g_prepost_table, elem); | |
1703 | if (--nalloc == 0) { | |
1704 | /* terminate the allocated list */ | |
1705 | elem->wqt_next_idx = WQT_IDX_MAX; | |
1706 | break; | |
1707 | } | |
1708 | } | |
1709 | assert(nalloc == 0); | |
1710 | if (!next) | |
1711 | cache->head = WQT_IDX_MAX; | |
1712 | else | |
1713 | cache->head = next->wqt_id.id; | |
1714 | /* assert that we don't have mis-matched book keeping */ | |
1715 | assert(!(cache->head == WQT_IDX_MAX && cache->avail > 0)); | |
1716 | enable_preemption(); | |
1717 | elem = first; | |
1718 | goto out; | |
1719 | } | |
1720 | enable_preemption(); | |
1721 | ||
1722 | do_alloc: | |
1723 | /* fall-back to standard table allocation */ | |
1724 | elem = wq_table_alloc_elem(&g_prepost_table, type, nelem); | |
1725 | if (!elem) | |
1726 | return NULL; | |
1727 | ||
1728 | out: | |
1729 | wqp = (struct wq_prepost *)elem; | |
1730 | wqp_do_alloc_stats(elem); | |
1731 | return wqp; | |
1732 | } | |
1733 | ||
1734 | /* | |
1735 | static void wq_prepost_realloc(struct wq_prepost *wqp, int type) | |
1736 | { | |
1737 | wq_table_realloc_elem(&g_prepost_table, &wqp->wqte, type); | |
1738 | } | |
1739 | */ | |
1740 | ||
1741 | static void wq_prepost_invalidate(struct wq_prepost *wqp) | |
1742 | { | |
1743 | wqt_elem_invalidate(&wqp->wqte); | |
1744 | } | |
1745 | ||
1746 | static struct wq_prepost *wq_prepost_get(uint64_t wqp_id) | |
1747 | { | |
1748 | struct wqt_elem *elem; | |
1749 | ||
1750 | elem = wq_table_get_elem(&g_prepost_table, wqp_id); | |
1751 | return (struct wq_prepost *)elem; | |
1752 | } | |
1753 | ||
1754 | static void wq_prepost_put(struct wq_prepost *wqp) | |
1755 | { | |
1756 | wq_table_put_elem(&g_prepost_table, (struct wqt_elem *)wqp); | |
1757 | } | |
1758 | ||
1759 | static int wq_prepost_rlink(struct wq_prepost *parent, struct wq_prepost *child) | |
1760 | { | |
1761 | return wqt_elem_list_link(&g_prepost_table, &parent->wqte, &child->wqte); | |
1762 | } | |
1763 | ||
1764 | static struct wq_prepost *wq_prepost_get_rnext(struct wq_prepost *head) | |
1765 | { | |
1766 | struct wqt_elem *elem; | |
1767 | struct wq_prepost *wqp; | |
1768 | uint64_t id; | |
1769 | ||
1770 | elem = wqt_elem_list_next(&g_prepost_table, &head->wqte); | |
1771 | if (!elem) | |
1772 | return NULL; | |
1773 | id = elem->wqt_id.id; | |
1774 | elem = wq_table_get_elem(&g_prepost_table, id); | |
1775 | ||
1776 | if (!elem) | |
1777 | return NULL; | |
1778 | wqp = (struct wq_prepost *)elem; | |
1779 | if (elem->wqt_id.id != id || | |
1780 | wqp_type(wqp) != WQP_POST || | |
1781 | wqp->wqp_post.wqp_next_id != head->wqp_prepostid.id) { | |
1782 | wq_table_put_elem(&g_prepost_table, elem); | |
1783 | return NULL; | |
1784 | } | |
1785 | ||
1786 | return wqp; | |
1787 | } | |
1788 | ||
1789 | static void wq_prepost_reset_rnext(struct wq_prepost *wqp) | |
1790 | { | |
1791 | wqt_elem_reset_next(&g_prepost_table, &wqp->wqte); | |
1792 | } | |
1793 | ||
1794 | ||
1795 | /** | |
1796 | * remove 'wqp' from the prepost list on 'wqset' | |
1797 | * | |
1798 | * Conditions: | |
1799 | * wqset is locked | |
1800 | * caller holds a reference on wqp (and is responsible to release it) | |
1801 | * | |
1802 | * Result: | |
1803 | * wqp is invalidated, wqset is potentially updated with a new | |
1804 | * prepost ID, and the next element of the prepost list may be | |
1805 | * consumed as well (if the list contained only 2 objects) | |
1806 | */ | |
1807 | static int wq_prepost_remove(struct waitq_set *wqset, | |
1808 | struct wq_prepost *wqp) | |
1809 | { | |
1810 | int more_posts = 1; | |
1811 | uint64_t next_id = wqp->wqp_post.wqp_next_id; | |
1812 | uint64_t wqp_id = wqp->wqp_prepostid.id; | |
1813 | struct wq_prepost *prev_wqp, *next_wqp; | |
1814 | ||
1815 | assert(wqp_type(wqp) == WQP_POST); | |
1816 | ||
1817 | if (next_id == wqp_id) { | |
1818 | /* the list is singular and becoming empty */ | |
1819 | wqset->wqset_prepost_id = 0; | |
1820 | more_posts = 0; | |
1821 | goto out; | |
1822 | } | |
1823 | ||
1824 | prev_wqp = wq_prepost_get_rnext(wqp); | |
1825 | assert(prev_wqp != NULL); | |
1826 | assert(prev_wqp->wqp_post.wqp_next_id == wqp_id); | |
1827 | assert(prev_wqp->wqp_prepostid.id != wqp_id); | |
1828 | assert(wqp_type(prev_wqp) == WQP_POST); | |
1829 | ||
1830 | if (prev_wqp->wqp_prepostid.id == next_id) { | |
1831 | /* | |
1832 | * There are two items in the list, and we're removing one. We | |
1833 | * only need to keep the WQP_WQ pointer from 'prev_wqp' | |
1834 | */ | |
1835 | wqset->wqset_prepost_id = prev_wqp->wqp_post.wqp_wq_id; | |
1836 | wq_prepost_invalidate(prev_wqp); | |
1837 | wq_prepost_put(prev_wqp); | |
1838 | more_posts = 0; | |
1839 | goto out; | |
1840 | } | |
1841 | ||
1842 | /* prev->next = next */ | |
1843 | prev_wqp->wqp_post.wqp_next_id = next_id; | |
1844 | ||
1845 | /* next->prev = prev */ | |
1846 | next_wqp = wq_prepost_get(next_id); | |
1847 | assert(next_wqp != NULL); | |
1848 | assert(next_wqp != wqp); | |
1849 | assert(next_wqp != prev_wqp); | |
1850 | assert(wqp_type(next_wqp) == WQP_POST); | |
1851 | ||
1852 | wq_prepost_reset_rnext(next_wqp); | |
1853 | wq_prepost_rlink(next_wqp, prev_wqp); | |
1854 | ||
1855 | /* If we remove the head of the list, update the wqset */ | |
1856 | if (wqp_id == wqset->wqset_prepost_id) | |
1857 | wqset->wqset_prepost_id = next_id; | |
1858 | ||
1859 | wq_prepost_put(prev_wqp); | |
1860 | wq_prepost_put(next_wqp); | |
1861 | ||
1862 | out: | |
1863 | wq_prepost_reset_rnext(wqp); | |
1864 | wq_prepost_invalidate(wqp); | |
1865 | return more_posts; | |
1866 | } | |
1867 | ||
1868 | static struct wq_prepost *wq_prepost_rfirst(uint64_t id) | |
1869 | { | |
1870 | struct wqt_elem *elem; | |
1871 | elem = wqt_elem_list_first(&g_prepost_table, id); | |
1872 | wqp_do_alloc_stats(elem); | |
1873 | return (struct wq_prepost *)(void *)elem; | |
1874 | } | |
1875 | ||
1876 | static struct wq_prepost *wq_prepost_rpop(uint64_t *id, int type) | |
1877 | { | |
1878 | struct wqt_elem *elem; | |
1879 | elem = wqt_elem_list_pop(&g_prepost_table, id, type); | |
1880 | wqp_do_alloc_stats(elem); | |
1881 | return (struct wq_prepost *)(void *)elem; | |
1882 | } | |
1883 | ||
1884 | static void wq_prepost_release_rlist(struct wq_prepost *wqp) | |
1885 | { | |
1886 | int nelem = 0; | |
1887 | struct wqp_cache *cache; | |
1888 | struct wqt_elem *elem; | |
1889 | ||
1890 | if (!wqp) | |
1891 | return; | |
1892 | ||
1893 | elem = &wqp->wqte; | |
1894 | ||
1895 | /* | |
1896 | * These are reserved elements: release them back to the per-cpu pool | |
1897 | * if our cache is running low. | |
1898 | */ | |
1899 | disable_preemption(); | |
1900 | cache = &PROCESSOR_DATA(current_processor(), wqp_cache); | |
1901 | if (cache->avail < WQP_CACHE_MAX) { | |
1902 | struct wqt_elem *tmp = NULL; | |
1903 | if (cache->head != WQT_IDX_MAX) | |
1904 | tmp = wqt_elem_list_first(&g_prepost_table, cache->head); | |
1905 | nelem = wqt_elem_list_link(&g_prepost_table, elem, tmp); | |
1906 | cache->head = elem->wqt_id.id; | |
1907 | cache->avail += nelem; | |
1908 | enable_preemption(); | |
1909 | return; | |
1910 | } | |
1911 | enable_preemption(); | |
1912 | ||
1913 | /* release these elements back to the main table */ | |
1914 | nelem = wqt_elem_list_release(&g_prepost_table, elem, WQT_RESERVED); | |
1915 | ||
1916 | #if CONFIG_WAITQ_STATS | |
1917 | g_prepost_table.nreserved_releases += 1; | |
1918 | OSDecrementAtomic64(&g_prepost_table.nreservations); | |
1919 | #endif | |
1920 | } | |
1921 | ||
1922 | typedef int (*wqp_callback_func)(struct waitq_set *wqset, | |
1923 | void *ctx, | |
1924 | struct wq_prepost *wqp, | |
1925 | struct waitq *waitq); | |
1926 | ||
1927 | /** | |
1928 | * iterate over a chain of preposts associated with a waitq set. | |
1929 | * | |
1930 | * Conditions: | |
1931 | * wqset is locked | |
1932 | * | |
1933 | * Notes: | |
1934 | * This loop performs automatic prepost chain management / culling, and | |
1935 | * may reset or adjust the waitq set's prepost ID pointer. If you don't | |
1936 | * want this extra processing, you can use wq_prepost_iterate(). | |
1937 | */ | |
1938 | static int wq_prepost_foreach_locked(struct waitq_set *wqset, | |
1939 | void *ctx, wqp_callback_func cb) | |
1940 | { | |
1941 | int ret; | |
1942 | struct wq_prepost *wqp, *tmp_wqp; | |
1943 | ||
1944 | if (!wqset || !wqset->wqset_prepost_id) | |
1945 | return WQ_ITERATE_SUCCESS; | |
1946 | ||
1947 | restart: | |
1948 | wqp = wq_prepost_get(wqset->wqset_prepost_id); | |
1949 | if (!wqp) { | |
1950 | /* | |
1951 | * The prepost object is no longer valid, reset the waitq | |
1952 | * set's prepost id. | |
1953 | */ | |
1954 | wqset->wqset_prepost_id = 0; | |
1955 | return WQ_ITERATE_SUCCESS; | |
1956 | } | |
1957 | ||
1958 | if (wqp_type(wqp) == WQP_WQ) { | |
1959 | uint64_t __assert_only wqp_id = wqp->wqp_prepostid.id; | |
1960 | if (cb) | |
1961 | ret = cb(wqset, ctx, wqp, wqp->wqp_wq.wqp_wq_ptr); | |
1962 | ||
1963 | switch (ret) { | |
1964 | case WQ_ITERATE_INVALIDATE_CONTINUE: | |
1965 | /* the caller wants to remove the only prepost here */ | |
1966 | assert(wqp_id == wqset->wqset_prepost_id); | |
1967 | wqset->wqset_prepost_id = 0; | |
1968 | /* fall through */ | |
1969 | case WQ_ITERATE_CONTINUE: | |
1970 | wq_prepost_put(wqp); | |
1971 | ret = WQ_ITERATE_SUCCESS; | |
1972 | break; | |
1973 | case WQ_ITERATE_RESTART: | |
1974 | wq_prepost_put(wqp); | |
1975 | /* fall through */ | |
1976 | case WQ_ITERATE_DROPPED: | |
1977 | goto restart; | |
1978 | default: | |
1979 | wq_prepost_put(wqp); | |
1980 | break; | |
1981 | } | |
1982 | return ret; | |
1983 | } | |
1984 | ||
1985 | assert(wqp->wqp_prepostid.id == wqset->wqset_prepost_id); | |
1986 | assert(wqp_type(wqp) == WQP_POST); | |
1987 | ||
1988 | /* | |
1989 | * At this point we know we have a list of POST objects. | |
1990 | * Grab a handle to the last element in the list and start | |
1991 | * the iteration. | |
1992 | */ | |
1993 | tmp_wqp = wq_prepost_get_rnext(wqp); | |
1994 | assert(tmp_wqp != NULL && wqp_type(tmp_wqp) == WQP_POST); | |
1995 | ||
1996 | uint64_t last_id = tmp_wqp->wqp_prepostid.id; | |
1997 | wq_prepost_put(tmp_wqp); | |
1998 | ||
1999 | ret = WQ_ITERATE_SUCCESS; | |
2000 | for (;;) { | |
2001 | uint64_t wqp_id, first_id, next_id; | |
2002 | ||
2003 | wqp_id = wqp->wqp_prepostid.id; | |
2004 | first_id = wqset->wqset_prepost_id; | |
2005 | next_id = wqp->wqp_post.wqp_next_id; | |
2006 | ||
2007 | /* grab the WQP_WQ object this _POST points to */ | |
2008 | tmp_wqp = wq_prepost_get(wqp->wqp_post.wqp_wq_id); | |
2009 | if (!tmp_wqp) { | |
2010 | /* | |
2011 | * This WQP_POST object points to an invalid | |
2012 | * WQP_WQ object - remove the POST object from | |
2013 | * the list. | |
2014 | */ | |
2015 | if (wq_prepost_remove(wqset, wqp) == 0) { | |
2016 | wq_prepost_put(wqp); | |
2017 | goto restart; | |
2018 | } | |
2019 | goto next_prepost; | |
2020 | } | |
2021 | assert(wqp_type(tmp_wqp) == WQP_WQ); | |
2022 | /* | |
2023 | * make the callback: note that this could remove 'wqp' or | |
2024 | * drop the lock on our waitq set. We need to re-validate | |
2025 | * our state when this function returns. | |
2026 | */ | |
2027 | if (cb) | |
2028 | ret = cb(wqset, ctx, wqp, | |
2029 | tmp_wqp->wqp_wq.wqp_wq_ptr); | |
2030 | wq_prepost_put(tmp_wqp); | |
2031 | ||
2032 | switch (ret) { | |
2033 | case WQ_ITERATE_CONTINUE: | |
2034 | /* continue iteration */ | |
2035 | break; | |
2036 | case WQ_ITERATE_INVALIDATE_CONTINUE: | |
2037 | assert(next_id == wqp->wqp_post.wqp_next_id); | |
2038 | if (wq_prepost_remove(wqset, wqp) == 0) { | |
2039 | wq_prepost_put(wqp); | |
2040 | goto restart; | |
2041 | } | |
2042 | goto next_prepost; | |
2043 | case WQ_ITERATE_RESTART: | |
2044 | wq_prepost_put(wqp); | |
2045 | /* fall-through */ | |
2046 | case WQ_ITERATE_DROPPED: | |
2047 | /* the callback dropped the ref to wqp: just restart */ | |
2048 | goto restart; | |
2049 | default: | |
2050 | /* break out of the iteration for some other reason */ | |
2051 | goto finish_prepost_foreach; | |
2052 | } | |
2053 | ||
2054 | /* | |
2055 | * the set lock may have been dropped during callback, | |
2056 | * if something looks different, restart the prepost iteration | |
2057 | */ | |
2058 | if (!wqp_is_valid(wqp) || | |
2059 | (wqp->wqp_post.wqp_next_id != next_id) || | |
2060 | wqset->wqset_prepost_id != first_id) { | |
2061 | wq_prepost_put(wqp); | |
2062 | goto restart; | |
2063 | } | |
2064 | ||
2065 | next_prepost: | |
2066 | /* this was the last object in the list */ | |
2067 | if (wqp_id == last_id) | |
2068 | break; | |
2069 | ||
2070 | /* get the next object */ | |
2071 | tmp_wqp = wq_prepost_get(next_id); | |
2072 | if (!tmp_wqp) { | |
2073 | /* | |
2074 | * At this point we've already checked our state | |
2075 | * after the callback (which may have dropped the set | |
2076 | * lock). If we find an invalid member of the list | |
2077 | * then something is wrong. | |
2078 | */ | |
2079 | panic("Invalid WQP_POST member 0x%llx in waitq set " | |
2080 | "0x%llx prepost list (first:%llx, " | |
2081 | "wqp:%p)", | |
2082 | next_id, wqset->wqset_id, first_id, wqp); | |
2083 | } | |
2084 | wq_prepost_put(wqp); | |
2085 | wqp = tmp_wqp; | |
2086 | ||
2087 | assert(wqp_type(wqp) == WQP_POST); | |
2088 | } | |
2089 | ||
2090 | finish_prepost_foreach: | |
2091 | wq_prepost_put(wqp); | |
2092 | if (ret == WQ_ITERATE_CONTINUE) | |
2093 | ret = WQ_ITERATE_SUCCESS; | |
2094 | ||
2095 | return ret; | |
2096 | } | |
2097 | ||
2098 | /** | |
2099 | * Perform a simple loop over a chain of prepost objects | |
2100 | * | |
2101 | * Conditions: | |
2102 | * If 'prepost_id' is associated with a waitq (set) then that object must | |
2103 | * be locked before calling this function. | |
2104 | * Callback function, 'cb', must be able to handle a NULL wqset pointer | |
2105 | * and a NULL waitq pointer! | |
2106 | * | |
2107 | * Notes: | |
2108 | * This prepost chain iteration will _not_ automatically adjust any chain | |
2109 | * element or linkage. This is the responsibility of the caller! If you | |
2110 | * want automatic prepost chain management (at a cost of extra CPU time), | |
2111 | * you can use: wq_prepost_foreach_locked(). | |
2112 | */ | |
2113 | static int wq_prepost_iterate(uint64_t prepost_id, | |
2114 | void *ctx, wqp_callback_func cb) | |
2115 | { | |
2116 | int ret; | |
2117 | struct wq_prepost *wqp; | |
2118 | ||
2119 | if (!prepost_id) | |
2120 | return WQ_ITERATE_SUCCESS; | |
2121 | ||
2122 | wqp = wq_prepost_get(prepost_id); | |
2123 | if (!wqp) | |
2124 | return WQ_ITERATE_SUCCESS; | |
2125 | ||
2126 | if (wqp_type(wqp) == WQP_WQ) { | |
2127 | ret = WQ_ITERATE_SUCCESS; | |
2128 | if (cb) | |
2129 | ret = cb(NULL, ctx, wqp, wqp->wqp_wq.wqp_wq_ptr); | |
2130 | ||
2131 | if (ret != WQ_ITERATE_DROPPED) | |
2132 | wq_prepost_put(wqp); | |
2133 | return ret; | |
2134 | } | |
2135 | ||
2136 | assert(wqp->wqp_prepostid.id == prepost_id); | |
2137 | assert(wqp_type(wqp) == WQP_POST); | |
2138 | ||
2139 | /* at this point we know we have a list of POST objects */ | |
2140 | uint64_t next_id; | |
2141 | ||
2142 | ret = WQ_ITERATE_CONTINUE; | |
2143 | do { | |
2144 | struct wq_prepost *tmp_wqp; | |
2145 | struct waitq *wq = NULL; | |
2146 | ||
2147 | next_id = wqp->wqp_post.wqp_next_id; | |
2148 | ||
2149 | /* grab the WQP_WQ object this _POST points to */ | |
2150 | tmp_wqp = wq_prepost_get(wqp->wqp_post.wqp_wq_id); | |
2151 | if (tmp_wqp) { | |
2152 | assert(wqp_type(tmp_wqp) == WQP_WQ); | |
2153 | wq = tmp_wqp->wqp_wq.wqp_wq_ptr; | |
2154 | } | |
2155 | ||
2156 | if (cb) | |
2157 | ret = cb(NULL, ctx, wqp, wq); | |
2158 | if (tmp_wqp) | |
2159 | wq_prepost_put(tmp_wqp); | |
2160 | ||
2161 | if (ret != WQ_ITERATE_CONTINUE) | |
2162 | break; | |
2163 | ||
2164 | tmp_wqp = wq_prepost_get(next_id); | |
2165 | if (!tmp_wqp) { | |
2166 | /* | |
2167 | * the chain is broken: nothing we can do here besides | |
2168 | * bail from the iteration. | |
2169 | */ | |
2170 | ret = WQ_ITERATE_ABORTED; | |
2171 | break; | |
2172 | } | |
2173 | ||
2174 | wq_prepost_put(wqp); | |
2175 | wqp = tmp_wqp; | |
2176 | ||
2177 | assert(wqp_type(wqp) == WQP_POST); | |
2178 | } while (next_id != prepost_id); | |
2179 | ||
2180 | if (ret != WQ_ITERATE_DROPPED) | |
2181 | wq_prepost_put(wqp); | |
2182 | ||
2183 | if (ret == WQ_ITERATE_CONTINUE) | |
2184 | ret = WQ_ITERATE_SUCCESS; | |
2185 | return ret; | |
2186 | } | |
2187 | ||
2188 | ||
2189 | struct _is_posted_ctx { | |
2190 | struct waitq *posting_wq; | |
2191 | int did_prepost; | |
2192 | }; | |
2193 | ||
2194 | static int wq_is_preposted_on_set_cb(struct waitq_set *wqset, void *ctx, | |
2195 | struct wq_prepost *wqp, struct waitq *waitq) | |
2196 | { | |
2197 | struct _is_posted_ctx *pctx = (struct _is_posted_ctx *)ctx; | |
2198 | ||
2199 | (void)wqset; | |
2200 | (void)wqp; | |
2201 | ||
2202 | /* | |
2203 | * Don't early-out, run through the _entire_ list: | |
2204 | * This ensures that we retain a minimum number of invalid elements. | |
2205 | */ | |
2206 | if (pctx->posting_wq == waitq) | |
2207 | pctx->did_prepost = 1; | |
2208 | ||
2209 | return WQ_ITERATE_CONTINUE; | |
2210 | } | |
2211 | ||
2212 | ||
2213 | /** | |
2214 | * checks if 'waitq' has already preposted on 'wqset' | |
2215 | * | |
2216 | * Parameters: | |
2217 | * waitq The waitq that's preposting | |
2218 | * wqset The set onto which waitq may be preposted | |
2219 | * | |
2220 | * Conditions: | |
2221 | * both waitq and wqset are locked | |
2222 | * | |
2223 | * Returns non-zero if 'waitq' has already preposted to 'wqset' | |
2224 | */ | |
2225 | static int wq_is_preposted_on_set(struct waitq *waitq, struct waitq_set *wqset) | |
2226 | { | |
2227 | int ret; | |
2228 | struct _is_posted_ctx pctx; | |
2229 | ||
2230 | /* | |
2231 | * If the set's only prepost matches the waitq's prepost ID, | |
2232 | * then it obviously already preposted to the set. | |
2233 | */ | |
2234 | if (waitq->waitq_prepost_id != 0 && | |
2235 | wqset->wqset_prepost_id == waitq->waitq_prepost_id) | |
2236 | return 1; | |
2237 | ||
2238 | /* use full prepost iteration: always trim the list */ | |
2239 | pctx.posting_wq = waitq; | |
2240 | pctx.did_prepost = 0; | |
2241 | ret = wq_prepost_foreach_locked(wqset, (void *)&pctx, | |
2242 | wq_is_preposted_on_set_cb); | |
2243 | return pctx.did_prepost; | |
2244 | } | |
2245 | ||
2246 | static struct wq_prepost *wq_get_prepost_obj(uint64_t *reserved, int type) | |
2247 | { | |
2248 | struct wq_prepost *wqp = NULL; | |
2249 | /* | |
2250 | * don't fail just because the caller doesn't have enough | |
2251 | * reservations, we've kept a low-water mark on the prepost table, | |
2252 | * so there should be some available for us. | |
2253 | */ | |
2254 | if (reserved && *reserved) { | |
2255 | wqp = wq_prepost_rpop(reserved, type); | |
2256 | } else { | |
2257 | /* | |
2258 | * TODO: if in interrupt context, grab from a special | |
2259 | * region / reserved list! | |
2260 | */ | |
2261 | wqp = wq_prepost_alloc(type, 1); | |
2262 | } | |
2263 | ||
2264 | if (wqp == NULL) | |
2265 | panic("Couldn't allocate prepost object!"); | |
2266 | return wqp; | |
2267 | } | |
2268 | ||
2269 | ||
2270 | /** | |
2271 | * prepost a waitq onto a waitq set | |
2272 | * | |
2273 | * Parameters: | |
2274 | * wqset The set onto which waitq will be preposted | |
2275 | * waitq The waitq that's preposting | |
2276 | * reserved List (wqt_elem_list_ style) of pre-allocated prepost elements | |
2277 | * Could be NULL | |
2278 | * | |
2279 | * Conditions: | |
2280 | * both wqset and waitq are locked | |
2281 | * | |
2282 | * Notes: | |
2283 | * If reserved is NULL, this may block on prepost table growth. | |
2284 | */ | |
2285 | static void wq_prepost_do_post_locked(struct waitq_set *wqset, | |
2286 | struct waitq *waitq, | |
2287 | uint64_t *reserved) | |
2288 | { | |
2289 | struct wq_prepost *wqp_post, *wqp_head, *wqp_tail; | |
2290 | ||
2291 | assert(waitq_held(waitq) && waitq_held(&wqset->wqset_q)); | |
2292 | ||
2293 | /* | |
2294 | * nothing to do if it's already preposted: | |
2295 | * note that this also culls any invalid prepost objects | |
2296 | */ | |
2297 | if (wq_is_preposted_on_set(waitq, wqset)) | |
2298 | return; | |
2299 | ||
2300 | /* | |
2301 | * This function is called because an event is being posted to 'waitq'. | |
2302 | * We need a prepost object associated with this queue. Allocate one | |
2303 | * now if the waitq isn't already associated with one. | |
2304 | */ | |
2305 | if (waitq->waitq_prepost_id == 0) { | |
2306 | struct wq_prepost *wqp; | |
2307 | wqp = wq_get_prepost_obj(reserved, WQP_WQ); | |
2308 | wqp->wqp_wq.wqp_wq_ptr = waitq; | |
2309 | wqp_set_valid(wqp); | |
2310 | waitq->waitq_prepost_id = wqp->wqp_prepostid.id; | |
2311 | wq_prepost_put(wqp); | |
2312 | } | |
2313 | ||
2314 | #if CONFIG_WAITQ_STATS | |
2315 | g_prepost_table.npreposts += 1; | |
2316 | #endif | |
2317 | ||
2318 | wqdbg_v("preposting waitq %p (0x%llx) to set 0x%llx", | |
2319 | (void *)VM_KERNEL_UNSLIDE_OR_PERM(waitq), | |
2320 | waitq->waitq_prepost_id, wqset->wqset_id); | |
2321 | ||
2322 | if (wqset->wqset_prepost_id == 0) { | |
2323 | /* the set has no previous preposts */ | |
2324 | wqset->wqset_prepost_id = waitq->waitq_prepost_id; | |
2325 | return; | |
2326 | } | |
2327 | ||
2328 | wqp_head = wq_prepost_get(wqset->wqset_prepost_id); | |
2329 | if (!wqp_head) { | |
2330 | /* the previous prepost has become invalid */ | |
2331 | wqset->wqset_prepost_id = waitq->waitq_prepost_id; | |
2332 | return; | |
2333 | } | |
2334 | ||
2335 | assert(wqp_head->wqp_prepostid.id == wqset->wqset_prepost_id); | |
2336 | ||
2337 | /* | |
2338 | * If we get here, we're going to need at least one new wq_prepost | |
2339 | * object. If the previous wqset_prepost_id points to a WQP_WQ, we | |
2340 | * actually need to allocate 2 wq_prepost objects because the WQP_WQ | |
2341 | * is tied to the waitq and shared across all sets. | |
2342 | */ | |
2343 | wqp_post = wq_get_prepost_obj(reserved, WQP_POST); | |
2344 | ||
2345 | wqp_post->wqp_post.wqp_wq_id = waitq->waitq_prepost_id; | |
2346 | wqdbg_v("POST 0x%llx :: WQ 0x%llx", wqp_post->wqp_prepostid.id, | |
2347 | waitq->waitq_prepost_id); | |
2348 | ||
2349 | if (wqp_type(wqp_head) == WQP_WQ) { | |
2350 | /* | |
2351 | * We must replace the wqset_prepost_id with a pointer | |
2352 | * to two new WQP_POST objects | |
2353 | */ | |
2354 | uint64_t wqp_id = wqp_head->wqp_prepostid.id; | |
2355 | wqdbg_v("set 0x%llx previous had 1 WQ prepost (0x%llx): " | |
2356 | "replacing with two POST preposts", | |
2357 | wqset->wqset_id, wqp_id); | |
2358 | ||
2359 | /* drop the old reference */ | |
2360 | wq_prepost_put(wqp_head); | |
2361 | ||
2362 | /* grab another new object (the 2nd of two) */ | |
2363 | wqp_head = wq_get_prepost_obj(reserved, WQP_POST); | |
2364 | ||
2365 | /* point this one to the original WQP_WQ object */ | |
2366 | wqp_head->wqp_post.wqp_wq_id = wqp_id; | |
2367 | wqdbg_v("POST 0x%llx :: WQ 0x%llx", | |
2368 | wqp_head->wqp_prepostid.id, wqp_id); | |
2369 | ||
2370 | /* link it to the new wqp_post object allocated earlier */ | |
2371 | wqp_head->wqp_post.wqp_next_id = wqp_post->wqp_prepostid.id; | |
2372 | /* make the list a double-linked and circular */ | |
2373 | wq_prepost_rlink(wqp_head, wqp_post); | |
2374 | ||
2375 | /* | |
2376 | * Finish setting up the new prepost: point it back to the | |
2377 | * POST object we allocated to replace the original wqset | |
2378 | * WQ prepost object | |
2379 | */ | |
2380 | wqp_post->wqp_post.wqp_next_id = wqp_head->wqp_prepostid.id; | |
2381 | wq_prepost_rlink(wqp_post, wqp_head); | |
2382 | ||
2383 | /* mark objects valid, and reset the wqset prepost list head */ | |
2384 | wqp_set_valid(wqp_head); | |
2385 | wqp_set_valid(wqp_post); | |
2386 | wqset->wqset_prepost_id = wqp_head->wqp_prepostid.id; | |
2387 | ||
2388 | /* release both references */ | |
2389 | wq_prepost_put(wqp_head); | |
2390 | wq_prepost_put(wqp_post); | |
2391 | ||
2392 | wqdbg_v("set 0x%llx: 0x%llx/0x%llx -> 0x%llx/0x%llx -> 0x%llx", | |
2393 | wqset->wqset_id, wqset->wqset_prepost_id, | |
2394 | wqp_head->wqp_prepostid.id, wqp_head->wqp_post.wqp_next_id, | |
2395 | wqp_post->wqp_prepostid.id, | |
2396 | wqp_post->wqp_post.wqp_next_id); | |
2397 | return; | |
2398 | } | |
2399 | ||
2400 | assert(wqp_type(wqp_head) == WQP_POST); | |
2401 | ||
2402 | /* | |
2403 | * Add the new prepost to the end of the prepost list | |
2404 | */ | |
2405 | wqp_tail = wq_prepost_get_rnext(wqp_head); | |
2406 | assert(wqp_tail != NULL); | |
2407 | assert(wqp_tail->wqp_post.wqp_next_id == wqset->wqset_prepost_id); | |
2408 | ||
2409 | /* | |
2410 | * link the head to the new tail | |
2411 | * NOTE: this needs to happen first in case wqp_tail == wqp_head | |
2412 | */ | |
2413 | wq_prepost_reset_rnext(wqp_head); | |
2414 | wq_prepost_rlink(wqp_head, wqp_post); | |
2415 | ||
2416 | /* point the new object to the list head, and list tail */ | |
2417 | wqp_post->wqp_post.wqp_next_id = wqp_head->wqp_prepostid.id; | |
2418 | wq_prepost_rlink(wqp_post, wqp_tail); | |
2419 | ||
2420 | /* point the last item in the waitq set's list to the new object */ | |
2421 | wqp_tail->wqp_post.wqp_next_id = wqp_post->wqp_prepostid.id; | |
2422 | ||
2423 | wqp_set_valid(wqp_post); | |
2424 | ||
2425 | wq_prepost_put(wqp_head); | |
2426 | wq_prepost_put(wqp_tail); | |
2427 | wq_prepost_put(wqp_post); | |
2428 | ||
2429 | wqdbg_v("set 0x%llx (wqp:0x%llx) last_prepost:0x%llx, " | |
2430 | "new_prepost:0x%llx->0x%llx", wqset->wqset_id, | |
2431 | wqset->wqset_prepost_id, wqp_head->wqp_prepostid.id, | |
2432 | wqp_post->wqp_prepostid.id, wqp_post->wqp_post.wqp_next_id); | |
2433 | ||
2434 | return; | |
2435 | } | |
2436 | ||
2437 | ||
2438 | /* ---------------------------------------------------------------------- | |
2439 | * | |
2440 | * Stats collection / reporting | |
2441 | * | |
2442 | * ---------------------------------------------------------------------- */ | |
2443 | #if CONFIG_WAITQ_STATS | |
2444 | static void wq_table_stats(struct wq_table *table, struct wq_table_stats *stats) | |
2445 | { | |
2446 | stats->version = WAITQ_STATS_VERSION; | |
2447 | stats->table_elements = table->nelem; | |
2448 | stats->table_used_elems = table->used_elem; | |
2449 | stats->table_elem_sz = table->elem_sz; | |
2450 | stats->table_slabs = table->nslabs; | |
2451 | stats->table_slab_sz = table->slab_sz; | |
2452 | ||
2453 | stats->table_num_allocs = table->nallocs; | |
2454 | stats->table_num_preposts = table->npreposts; | |
2455 | stats->table_num_reservations = table->nreservations; | |
2456 | ||
2457 | stats->table_max_used = table->max_used; | |
2458 | stats->table_avg_used = table->avg_used; | |
2459 | stats->table_max_reservations = table->max_reservations; | |
2460 | stats->table_avg_reservations = table->avg_reservations; | |
2461 | } | |
2462 | ||
2463 | void waitq_link_stats(struct wq_table_stats *stats) | |
2464 | { | |
2465 | if (!stats) | |
2466 | return; | |
2467 | wq_table_stats(&g_linktable, stats); | |
2468 | } | |
2469 | ||
2470 | void waitq_prepost_stats(struct wq_table_stats *stats) | |
2471 | { | |
2472 | wq_table_stats(&g_prepost_table, stats); | |
2473 | } | |
2474 | #endif | |
2475 | ||
2476 | ||
2477 | /* ---------------------------------------------------------------------- | |
2478 | * | |
2479 | * Global Wait Queues | |
2480 | * | |
2481 | * ---------------------------------------------------------------------- */ | |
2482 | ||
2483 | static struct waitq g_boot_waitq; | |
2484 | static struct waitq *global_waitqs = &g_boot_waitq; | |
2485 | static uint32_t g_num_waitqs = 1; | |
2486 | ||
2487 | /* | |
2488 | * Zero out the used MSBs of the event. | |
2489 | */ | |
2490 | #define _CAST_TO_EVENT_MASK(event) ((uintptr_t)(event) & ((1ul << _EVENT_MASK_BITS) - 1ul)) | |
2491 | ||
2492 | /* | |
2493 | * The Jenkins "one at a time" hash. | |
2494 | * TBD: There may be some value to unrolling here, | |
2495 | * depending on the architecture. | |
2496 | */ | |
2497 | static __inline__ uint32_t waitq_hash(char *key, size_t length) | |
2498 | { | |
2499 | uint32_t hash = 0; | |
2500 | size_t i; | |
2501 | ||
2502 | for (i = 0; i < length; i++) { | |
2503 | hash += key[i]; | |
2504 | hash += (hash << 10); | |
2505 | hash ^= (hash >> 6); | |
2506 | } | |
2507 | ||
2508 | hash += (hash << 3); | |
2509 | hash ^= (hash >> 11); | |
2510 | hash += (hash << 15); | |
2511 | ||
2512 | hash &= (g_num_waitqs - 1); | |
2513 | return hash; | |
2514 | } | |
2515 | ||
2516 | /* return a global waitq pointer corresponding to the given event */ | |
2517 | struct waitq *_global_eventq(char *event, size_t event_length) | |
2518 | { | |
2519 | return &global_waitqs[waitq_hash(event, event_length)]; | |
2520 | } | |
2521 | ||
2522 | /* return an indexed global waitq pointer */ | |
2523 | struct waitq *global_waitq(int index) | |
2524 | { | |
2525 | return &global_waitqs[index % g_num_waitqs]; | |
2526 | } | |
2527 | ||
2528 | ||
2529 | #if CONFIG_WAITQ_STATS | |
2530 | /* this global is for lldb */ | |
2531 | const uint32_t g_nwaitq_btframes = NWAITQ_BTFRAMES; | |
2532 | struct wq_stats g_boot_stats; | |
2533 | struct wq_stats *g_waitq_stats = &g_boot_stats; | |
2534 | ||
2535 | static __inline__ void waitq_grab_backtrace(uintptr_t bt[NWAITQ_BTFRAMES], int skip) | |
2536 | { | |
2537 | uintptr_t buf[NWAITQ_BTFRAMES + skip]; | |
2538 | if (skip < 0) | |
2539 | skip = 0; | |
2540 | memset(buf, 0, (NWAITQ_BTFRAMES + skip) * sizeof(uintptr_t)); | |
2541 | fastbacktrace(buf, g_nwaitq_btframes + skip); | |
2542 | memcpy(&bt[0], &buf[skip], NWAITQ_BTFRAMES * sizeof(uintptr_t)); | |
2543 | } | |
2544 | ||
2545 | static __inline__ struct wq_stats *waitq_global_stats(struct waitq *waitq) { | |
2546 | struct wq_stats *wqs; | |
2547 | uint32_t idx; | |
2548 | ||
2549 | if (!waitq_is_global(waitq)) | |
2550 | return NULL; | |
2551 | ||
2552 | idx = (uint32_t)(((uintptr_t)waitq - (uintptr_t)global_waitqs) / sizeof(*waitq)); | |
2553 | assert(idx < g_num_waitqs); | |
2554 | wqs = &g_waitq_stats[idx]; | |
2555 | return wqs; | |
2556 | } | |
2557 | ||
2558 | static __inline__ void waitq_stats_count_wait(struct waitq *waitq) | |
2559 | { | |
2560 | struct wq_stats *wqs = waitq_global_stats(waitq); | |
2561 | if (wqs != NULL) { | |
2562 | wqs->waits++; | |
2563 | waitq_grab_backtrace(wqs->last_wait, 2); | |
2564 | } | |
2565 | } | |
2566 | ||
2567 | static __inline__ void waitq_stats_count_wakeup(struct waitq *waitq) | |
2568 | { | |
2569 | struct wq_stats *wqs = waitq_global_stats(waitq); | |
2570 | if (wqs != NULL) { | |
2571 | wqs->wakeups++; | |
2572 | waitq_grab_backtrace(wqs->last_wakeup, 2); | |
2573 | } | |
2574 | } | |
2575 | ||
2576 | static __inline__ void waitq_stats_count_clear_wakeup(struct waitq *waitq) | |
2577 | { | |
2578 | struct wq_stats *wqs = waitq_global_stats(waitq); | |
2579 | if (wqs != NULL) { | |
2580 | wqs->wakeups++; | |
2581 | wqs->clears++; | |
2582 | waitq_grab_backtrace(wqs->last_wakeup, 2); | |
2583 | } | |
2584 | } | |
2585 | ||
2586 | static __inline__ void waitq_stats_count_fail(struct waitq *waitq) | |
2587 | { | |
2588 | struct wq_stats *wqs = waitq_global_stats(waitq); | |
2589 | if (wqs != NULL) { | |
2590 | wqs->failed_wakeups++; | |
2591 | waitq_grab_backtrace(wqs->last_failed_wakeup, 2); | |
2592 | } | |
2593 | } | |
2594 | #else | |
2595 | #define waitq_stats_count_wait(q) do { } while (0) | |
2596 | #define waitq_stats_count_wakeup(q) do { } while (0) | |
2597 | #define waitq_stats_count_clear_wakeup(q) do { } while (0) | |
2598 | #define waitq_stats_count_fail(q) do { } while (0) | |
2599 | #endif | |
2600 | ||
2601 | int waitq_is_valid(struct waitq *waitq) | |
2602 | { | |
2603 | return (waitq != NULL) && ((waitq->waitq_type & ~1) == WQT_QUEUE); | |
2604 | } | |
2605 | ||
2606 | int waitq_set_is_valid(struct waitq_set *wqset) | |
2607 | { | |
2608 | return (wqset != NULL) && waitqs_is_set(wqset); | |
2609 | } | |
2610 | ||
2611 | int waitq_is_global(struct waitq *waitq) | |
2612 | { | |
2613 | if (waitq >= global_waitqs && waitq < global_waitqs + g_num_waitqs) | |
2614 | return 1; | |
2615 | return 0; | |
2616 | } | |
2617 | ||
2618 | int waitq_irq_safe(struct waitq *waitq) | |
2619 | { | |
2620 | /* global wait queues have this bit set on initialization */ | |
2621 | return waitq->waitq_irq; | |
2622 | } | |
2623 | ||
2624 | static uint32_t waitq_hash_size(void) | |
2625 | { | |
2626 | uint32_t hsize, queues; | |
2627 | ||
2628 | if (PE_parse_boot_argn("wqsize", &hsize, sizeof(hsize))) | |
2629 | return (hsize); | |
2630 | ||
2631 | queues = thread_max / 11; | |
2632 | hsize = P2ROUNDUP(queues * sizeof(struct waitq), PAGE_SIZE); | |
2633 | ||
2634 | return hsize; | |
2635 | } | |
2636 | ||
2637 | void waitq_bootstrap(void) | |
2638 | { | |
2639 | kern_return_t kret; | |
2640 | uint32_t whsize, qsz; | |
2641 | ||
2642 | wq_table_bootstrap(); | |
2643 | lt_init(); | |
2644 | wqp_init(); | |
2645 | ||
2646 | /* | |
2647 | * Determine the amount of memory we're willing to reserve for | |
2648 | * the waitqueue hash table | |
2649 | */ | |
2650 | whsize = waitq_hash_size(); | |
2651 | ||
2652 | /* Determine the number of waitqueues we can fit. */ | |
2653 | qsz = sizeof(struct waitq); | |
2654 | whsize = ROUNDDOWN(whsize, qsz); | |
2655 | g_num_waitqs = whsize / qsz; | |
2656 | ||
2657 | /* | |
2658 | * The hash algorithm requires that this be a power of 2, so we | |
2659 | * just mask off all the low-order bits. | |
2660 | */ | |
2661 | for (uint32_t i = 0; i < 31; i++) { | |
2662 | uint32_t bit = (1 << i); | |
2663 | if ((g_num_waitqs & bit) == g_num_waitqs) | |
2664 | break; | |
2665 | g_num_waitqs &= ~bit; | |
2666 | } | |
2667 | assert(g_num_waitqs > 0); | |
2668 | ||
2669 | /* Now determine how much memory we really need. */ | |
2670 | whsize = P2ROUNDUP(g_num_waitqs * qsz, PAGE_SIZE); | |
2671 | ||
2672 | wqdbg("allocating %d global queues (%d bytes)", g_num_waitqs, whsize); | |
2673 | kret = kernel_memory_allocate(kernel_map, (vm_offset_t *)&global_waitqs, | |
2674 | whsize, 0, KMA_KOBJECT|KMA_NOPAGEWAIT, VM_KERN_MEMORY_WAITQ); | |
2675 | if (kret != KERN_SUCCESS || global_waitqs == NULL) | |
2676 | panic("kernel_memory_allocate() failed to alloc global_waitqs" | |
2677 | ", error: %d, whsize: 0x%x", kret, whsize); | |
2678 | ||
2679 | #if CONFIG_WAITQ_STATS | |
2680 | whsize = P2ROUNDUP(g_num_waitqs * sizeof(struct wq_stats), PAGE_SIZE); | |
2681 | kret = kernel_memory_allocate(kernel_map, (vm_offset_t *)&g_waitq_stats, | |
2682 | whsize, 0, KMA_KOBJECT|KMA_NOPAGEWAIT, VM_KERN_MEMORY_WAITQ); | |
2683 | if (kret != KERN_SUCCESS || global_waitqs == NULL) | |
2684 | panic("kernel_memory_allocate() failed to alloc g_waitq_stats" | |
2685 | ", error: %d, whsize: 0x%x", kret, whsize); | |
2686 | memset(g_waitq_stats, 0, whsize); | |
2687 | #endif | |
2688 | ||
2689 | for (uint32_t i = 0; i < g_num_waitqs; i++) { | |
2690 | waitq_init(&global_waitqs[i], SYNC_POLICY_FIFO|SYNC_POLICY_DISABLE_IRQ); | |
2691 | } | |
2692 | ||
2693 | ||
2694 | waitq_set_zone = zinit(sizeof(struct waitq_set), | |
2695 | WAITQ_SET_MAX * sizeof(struct waitq_set), | |
2696 | sizeof(struct waitq_set), | |
2697 | "waitq sets"); | |
2698 | zone_change(waitq_set_zone, Z_NOENCRYPT, TRUE); | |
2699 | } | |
2700 | ||
2701 | ||
2702 | /* ---------------------------------------------------------------------- | |
2703 | * | |
2704 | * Wait Queue Implementation | |
2705 | * | |
2706 | * ---------------------------------------------------------------------- */ | |
2707 | ||
2708 | /* | |
2709 | * Double the standard lock timeout, because wait queues tend | |
2710 | * to iterate over a number of threads - locking each. If there is | |
2711 | * a problem with a thread lock, it normally times out at the wait | |
2712 | * queue level first, hiding the real problem. | |
2713 | */ | |
2714 | /* For x86, the hardware timeout is in TSC units. */ | |
2715 | #if defined(__i386__) || defined(__x86_64__) | |
2716 | #define hwLockTimeOut LockTimeOutTSC | |
2717 | #else | |
2718 | #define hwLockTimeOut LockTimeOut | |
2719 | #endif | |
2720 | ||
2721 | void waitq_lock(struct waitq *wq) | |
2722 | { | |
2723 | if (__improbable(hw_lock_to(&(wq)->waitq_interlock, | |
2724 | hwLockTimeOut * 2) == 0)) { | |
2725 | boolean_t wql_acquired = FALSE; | |
2726 | ||
2727 | while (machine_timeout_suspended()) { | |
2728 | #if defined(__i386__) || defined(__x86_64__) | |
2729 | /* | |
2730 | * i386/x86_64 return with preemption disabled on a | |
2731 | * timeout for diagnostic purposes. | |
2732 | */ | |
2733 | mp_enable_preemption(); | |
2734 | #endif | |
2735 | wql_acquired = hw_lock_to(&(wq)->waitq_interlock, | |
2736 | hwLockTimeOut * 2); | |
2737 | if (wql_acquired) | |
2738 | break; | |
2739 | } | |
2740 | if (wql_acquired == FALSE) | |
2741 | panic("waitq deadlock - waitq=%p, cpu=%d\n", | |
2742 | wq, cpu_number()); | |
2743 | } | |
2744 | assert(waitq_held(wq)); | |
2745 | } | |
2746 | ||
2747 | void waitq_unlock(struct waitq *wq) | |
2748 | { | |
2749 | assert(waitq_held(wq)); | |
2750 | hw_lock_unlock(&(wq)->waitq_interlock); | |
2751 | } | |
2752 | ||
2753 | ||
2754 | /** | |
2755 | * clear the thread-related waitq state | |
2756 | * | |
2757 | * Conditions: | |
2758 | * 'thread' is locked | |
2759 | */ | |
2760 | static inline void thread_clear_waitq_state(thread_t thread) | |
2761 | { | |
2762 | thread->waitq = NULL; | |
2763 | thread->wait_event = NO_EVENT64; | |
2764 | thread->at_safe_point = FALSE; | |
2765 | } | |
2766 | ||
2767 | ||
2768 | typedef thread_t (*waitq_select_cb)(void *ctx, struct waitq *waitq, | |
2769 | int is_global, thread_t thread); | |
2770 | ||
2771 | struct waitq_select_args { | |
2772 | /* input parameters */ | |
2773 | struct waitq *posted_waitq; | |
2774 | struct waitq *waitq; | |
2775 | event64_t event; | |
2776 | waitq_select_cb select_cb; | |
2777 | void *select_ctx; | |
2778 | ||
2779 | uint64_t *reserved_preposts; | |
2780 | ||
2781 | /* output parameters */ | |
2782 | queue_t threadq; | |
2783 | int max_threads; | |
2784 | int *nthreads; | |
2785 | spl_t *spl; | |
2786 | }; | |
2787 | ||
2788 | static void do_waitq_select_n_locked(struct waitq_select_args *args); | |
2789 | ||
2790 | /** | |
2791 | * callback invoked once for every waitq set to which a waitq belongs | |
2792 | * | |
2793 | * Conditions: | |
2794 | * ctx->posted_waitq is locked | |
2795 | * 'link' points to a valid waitq set | |
2796 | * | |
2797 | * Notes: | |
2798 | * Takes the waitq set lock on the set pointed to by 'link' | |
2799 | * Calls do_waitq_select_n_locked() which could recurse back into | |
2800 | * this function if the waitq set is a member of other sets. | |
2801 | * If no threads were selected, it preposts the input waitq | |
2802 | * onto the waitq set pointed to by 'link'. | |
2803 | */ | |
2804 | static int waitq_select_walk_cb(struct waitq *waitq, void *ctx, | |
2805 | struct setid_link *link) | |
2806 | { | |
2807 | int ret = WQ_ITERATE_CONTINUE; | |
2808 | struct waitq_select_args args = *((struct waitq_select_args *)ctx); | |
2809 | struct waitq_set *wqset; | |
2810 | int get_spl = 0; | |
2811 | spl_t set_spl; | |
2812 | ||
2813 | (void)waitq; | |
2814 | assert(sl_type(link) == SLT_WQS); | |
2815 | ||
2816 | wqset = link->sl_wqs.sl_set; | |
2817 | args.waitq = &wqset->wqset_q; | |
2818 | ||
2819 | if (!waitq_irq_safe(waitq) && waitq_irq_safe(&wqset->wqset_q)) { | |
2820 | get_spl = 1; | |
2821 | set_spl = splsched(); | |
2822 | } | |
2823 | waitq_set_lock(wqset); | |
2824 | /* | |
2825 | * verify that the link wasn't invalidated just before | |
2826 | * we were able to take the lock. | |
2827 | */ | |
2828 | if (wqset->wqset_id != link->sl_set_id.id) | |
2829 | goto out_unlock; | |
2830 | ||
2831 | /* | |
2832 | * Find any threads waiting on this wait queue set, | |
2833 | * and recurse into any waitq set to which this set belongs. | |
2834 | */ | |
2835 | do_waitq_select_n_locked(&args); | |
2836 | ||
2837 | if (*(args.nthreads) > 0 || | |
2838 | (args.threadq && !queue_empty(args.threadq))) { | |
2839 | /* at least 1 thread was selected and returned: don't prepost */ | |
2840 | if (args.max_threads > 0 && | |
2841 | *(args.nthreads) >= args.max_threads) { | |
2842 | /* break out of the setid walk */ | |
2843 | ret = WQ_ITERATE_FOUND; | |
2844 | } | |
2845 | goto out_unlock; | |
2846 | } else { | |
2847 | /* | |
2848 | * No thread selected: prepost 'waitq' to 'wqset' | |
2849 | * if wqset can handle preposts and the event is set to 0. | |
2850 | * We also make sure to not post waitq sets to other sets. | |
2851 | * | |
2852 | * In the future, we may consider an optimization to prepost | |
2853 | * 'args.posted_waitq' directly to 'wqset' to avoid | |
2854 | * unnecessary data structure manipulations in the kqueue path | |
2855 | */ | |
2856 | if (args.event == NO_EVENT64 && waitq_set_can_prepost(wqset)) { | |
2857 | wq_prepost_do_post_locked(wqset, waitq, | |
2858 | args.reserved_preposts); | |
2859 | } | |
2860 | } | |
2861 | ||
2862 | out_unlock: | |
2863 | waitq_set_unlock(wqset); | |
2864 | if (get_spl) | |
2865 | splx(set_spl); | |
2866 | return ret; | |
2867 | } | |
2868 | ||
2869 | /** | |
2870 | * generic thread selection from a waitq (and sets to which the waitq belongs) | |
2871 | * | |
2872 | * Conditions: | |
2873 | * args->waitq (and args->posted_waitq) is locked | |
2874 | * | |
2875 | * Notes: | |
2876 | * Uses the optional select callback function to refine the selection | |
2877 | * of one or more threads from a waitq and any set to which the waitq | |
2878 | * belongs. The select callback is invoked once for every thread that | |
2879 | * is found to be waiting on the input args->waitq. | |
2880 | * | |
2881 | * If one or more threads are selected, this may disable interrupts. | |
2882 | * The previous interrupt state is returned in args->spl and should | |
2883 | * be used in a call to splx() if threads are returned to the caller. | |
2884 | */ | |
2885 | static void do_waitq_select_n_locked(struct waitq_select_args *args) | |
2886 | { | |
2887 | struct waitq *waitq = args->waitq; | |
2888 | int max_threads = args->max_threads; | |
2889 | thread_t thread = THREAD_NULL, first_thread = THREAD_NULL; | |
2890 | int global_q = 0; | |
2891 | unsigned long eventmask = 0; | |
2892 | int *nthreads = args->nthreads; | |
2893 | ||
2894 | assert(max_threads != 0); | |
2895 | ||
2896 | global_q = waitq_is_global(waitq); | |
2897 | if (global_q) { | |
2898 | eventmask = _CAST_TO_EVENT_MASK(args->event); | |
2899 | /* make sure this waitq accepts this event mask */ | |
2900 | if ((waitq->waitq_eventmask & eventmask) != eventmask) | |
2901 | return; | |
2902 | eventmask = 0; | |
2903 | } | |
2904 | ||
2905 | /* look through each thread waiting directly on the waitq */ | |
2906 | qe_foreach_element_safe(thread, &waitq->waitq_queue, links) { | |
2907 | thread_t t = THREAD_NULL; | |
2908 | assert(thread->waitq == waitq); | |
2909 | if (thread->wait_event == args->event) { | |
2910 | t = thread; | |
2911 | if (first_thread == THREAD_NULL) | |
2912 | first_thread = thread; | |
2913 | ||
2914 | /* allow the caller to futher refine the selection */ | |
2915 | if (args->select_cb) | |
2916 | t = args->select_cb(args->select_ctx, waitq, | |
2917 | global_q, thread); | |
2918 | if (t != THREAD_NULL) { | |
2919 | *nthreads += 1; | |
2920 | if (args->threadq) { | |
2921 | if (*nthreads == 1) | |
2922 | *(args->spl) = splsched(); | |
2923 | thread_lock(t); | |
2924 | thread_clear_waitq_state(t); | |
2925 | /* put locked thread on output queue */ | |
2926 | re_queue_tail(args->threadq, &t->links); | |
2927 | } | |
2928 | /* only enqueue up to 'max' threads */ | |
2929 | if (*nthreads >= max_threads && max_threads > 0) | |
2930 | break; | |
2931 | } | |
2932 | } | |
2933 | /* thread wasn't selected, and the waitq is global */ | |
2934 | if (t == THREAD_NULL && global_q) | |
2935 | eventmask |= _CAST_TO_EVENT_MASK(thread->wait_event); | |
2936 | } | |
2937 | ||
2938 | /* | |
2939 | * Update the eventmask of global queues: | |
2940 | * - If we selected all the threads in the queue, or we selected zero | |
2941 | * threads on the queue, set the eventmask to the calculated value | |
2942 | * (potentially 0 if we selected them all) | |
2943 | * - If we just pulled out a subset of threads from the queue, then we | |
2944 | * can't assume the calculated mask is complete (because we may not | |
2945 | * have made it through all the threads in the queue), so we have to | |
2946 | * leave it alone. | |
2947 | */ | |
2948 | if (global_q && (queue_empty(&waitq->waitq_queue) || *nthreads == 0)) | |
2949 | waitq->waitq_eventmask = (typeof(waitq->waitq_eventmask))eventmask; | |
2950 | ||
2951 | /* | |
2952 | * Grab the first thread in the queue if no other thread was selected. | |
2953 | * We can guarantee that no one has manipulated this thread because | |
2954 | * it's waiting on the given waitq, and we have that waitq locked. | |
2955 | */ | |
2956 | if (*nthreads == 0 && first_thread != THREAD_NULL && args->threadq) { | |
2957 | /* we know this is the first (and only) thread */ | |
2958 | ++(*nthreads); | |
2959 | *(args->spl) = splsched(); | |
2960 | thread_lock(first_thread); | |
2961 | thread_clear_waitq_state(first_thread); | |
2962 | re_queue_tail(args->threadq, &first_thread->links); | |
2963 | ||
2964 | /* update the eventmask on global queues */ | |
2965 | if (global_q && queue_empty(&waitq->waitq_queue)) | |
2966 | waitq->waitq_eventmask = 0; | |
2967 | } | |
2968 | ||
2969 | if (max_threads > 0 && *nthreads >= max_threads) | |
2970 | return; | |
2971 | ||
2972 | /* | |
2973 | * wait queues that are not in any sets | |
2974 | * are the bottom of the recursion | |
2975 | */ | |
2976 | if (!waitq->waitq_set_id) | |
2977 | return; | |
2978 | ||
2979 | /* check to see if the set ID for this wait queue is valid */ | |
2980 | struct setid_link *link = lt_get_link(waitq->waitq_set_id); | |
2981 | if (!link) { | |
2982 | /* the waitq set to which this waitq belonged, has been invalidated */ | |
2983 | waitq->waitq_set_id = 0; | |
2984 | return; | |
2985 | } | |
2986 | ||
2987 | lt_put_link(link); | |
2988 | ||
2989 | /* | |
2990 | * If this waitq is a member of any wait queue sets, we need to look | |
2991 | * for waiting thread(s) in any of those sets, and prepost all sets that | |
2992 | * don't have active waiters. | |
2993 | * | |
2994 | * Note that we do a local walk of this waitq's links - we manually | |
2995 | * recurse down wait queue set's with non-zero wqset_q.waitq_set_id | |
2996 | */ | |
2997 | (void)walk_setid_links(LINK_WALK_ONE_LEVEL, waitq, waitq->waitq_set_id, | |
2998 | SLT_WQS, (void *)args, waitq_select_walk_cb); | |
2999 | } | |
3000 | ||
3001 | /** | |
3002 | * main entry point for thread selection from a waitq | |
3003 | * | |
3004 | * Conditions: | |
3005 | * waitq is locked | |
3006 | * | |
3007 | * Returns: | |
3008 | * The number of threads waiting on 'waitq' for 'event' which have | |
3009 | * been placed onto the input 'threadq' | |
3010 | * | |
3011 | * Notes: | |
3012 | * The 'select_cb' function is invoked for every thread found waiting | |
3013 | * on 'waitq' for 'event'. The thread is _not_ locked upon callback | |
3014 | * invocation. This parameter may be NULL. | |
3015 | * | |
3016 | * If one or more threads are returned in 'threadq' then the caller is | |
3017 | * responsible to call splx() using the returned 'spl' value. Each | |
3018 | * returned thread is locked. | |
3019 | */ | |
3020 | static __inline__ int waitq_select_n_locked(struct waitq *waitq, | |
3021 | event64_t event, | |
3022 | waitq_select_cb select_cb, | |
3023 | void *select_ctx, | |
3024 | uint64_t *reserved_preposts, | |
3025 | queue_t threadq, | |
3026 | int max_threads, spl_t *spl) | |
3027 | { | |
3028 | int nthreads = 0; | |
3029 | ||
3030 | struct waitq_select_args args = { | |
3031 | .posted_waitq = waitq, | |
3032 | .waitq = waitq, | |
3033 | .event = event, | |
3034 | .select_cb = select_cb, | |
3035 | .select_ctx = select_ctx, | |
3036 | .reserved_preposts = reserved_preposts, | |
3037 | .threadq = threadq, | |
3038 | .max_threads = max_threads, | |
3039 | .nthreads = &nthreads, | |
3040 | .spl = spl, | |
3041 | }; | |
3042 | ||
3043 | do_waitq_select_n_locked(&args); | |
3044 | return nthreads; | |
3045 | } | |
3046 | ||
3047 | ||
3048 | /** | |
3049 | * callback function that uses thread parameters to determine wakeup eligibility | |
3050 | * | |
3051 | * Conditions: | |
3052 | * 'waitq' is locked | |
3053 | * 'thread' is not locked | |
3054 | */ | |
3055 | static thread_t waitq_select_one_cb(void *ctx, struct waitq *waitq, | |
3056 | int is_global, thread_t thread) | |
3057 | { | |
3058 | int fifo_q, realtime; | |
3059 | boolean_t thread_imp_donor = FALSE; | |
3060 | ||
3061 | (void)ctx; | |
3062 | (void)waitq; | |
3063 | (void)is_global; | |
3064 | realtime = 0; | |
3065 | ||
3066 | fifo_q = 1; /* default to FIFO for all queues for now */ | |
3067 | #if IMPORTANCE_INHERITANCE | |
3068 | if (is_global) | |
3069 | fifo_q = 0; /* 'thread_imp_donor' takes the place of FIFO checking */ | |
3070 | #endif | |
3071 | ||
3072 | if (thread->sched_pri >= BASEPRI_REALTIME) | |
3073 | realtime = 1; | |
3074 | ||
3075 | #if IMPORTANCE_INHERITANCE | |
3076 | /* | |
3077 | * Checking imp donor bit does not need thread lock or | |
3078 | * or task lock since we have the wait queue lock and | |
3079 | * thread can not be removed from it without acquiring | |
3080 | * wait queue lock. The imp donor bit may change | |
3081 | * once we read its value, but it is ok to wake | |
3082 | * a thread while someone drops importance assertion | |
3083 | * on the that thread. | |
3084 | */ | |
3085 | thread_imp_donor = task_is_importance_donor(thread->task); | |
3086 | #endif /* IMPORTANCE_INHERITANCE */ | |
3087 | ||
3088 | if (fifo_q || thread_imp_donor == TRUE | |
3089 | || realtime || (thread->options & TH_OPT_VMPRIV)) { | |
3090 | /* | |
3091 | * If this thread's task is an importance donor, | |
3092 | * or it's a realtime thread, or it's a VM privileged | |
3093 | * thread, OR the queue is marked as FIFO: | |
3094 | * select the thread | |
3095 | */ | |
3096 | return thread; | |
3097 | } | |
3098 | ||
3099 | /* by default, _don't_ select the thread */ | |
3100 | return THREAD_NULL; | |
3101 | } | |
3102 | ||
3103 | /** | |
3104 | * select a single thread from a waitq that's waiting for a given event | |
3105 | * | |
3106 | * Conditions: | |
3107 | * 'waitq' is locked | |
3108 | * | |
3109 | * Returns: | |
3110 | * A locked thread that's been removed from the waitq, but has not | |
3111 | * yet been put on a run queue. Caller is responsible to call splx | |
3112 | * with the '*spl' value. | |
3113 | */ | |
3114 | static thread_t waitq_select_one_locked(struct waitq *waitq, event64_t event, | |
3115 | uint64_t *reserved_preposts, | |
3116 | int priority, spl_t *spl) | |
3117 | { | |
3118 | int nthreads; | |
3119 | queue_head_t threadq; | |
3120 | ||
3121 | (void)priority; | |
3122 | ||
3123 | queue_init(&threadq); | |
3124 | ||
3125 | nthreads = waitq_select_n_locked(waitq, event, waitq_select_one_cb, NULL, | |
3126 | reserved_preposts, &threadq, 1, spl); | |
3127 | ||
3128 | /* if we selected a thread, return it (still locked) */ | |
3129 | if (!queue_empty(&threadq)) { | |
3130 | thread_t t; | |
3131 | queue_entry_t qe = dequeue_head(&threadq); | |
3132 | t = qe_element(qe, struct thread, links); | |
3133 | assert(queue_empty(&threadq)); /* there should be 1 entry */ | |
3134 | /* t has been locked and removed from all queues */ | |
3135 | return t; | |
3136 | } | |
3137 | ||
3138 | return THREAD_NULL; | |
3139 | } | |
3140 | ||
3141 | ||
3142 | struct select_thread_ctx { | |
3143 | thread_t thread; | |
3144 | event64_t event; | |
3145 | spl_t *spl; | |
3146 | }; | |
3147 | ||
3148 | /** | |
3149 | * link walk callback invoked once for each set to which a waitq belongs | |
3150 | * | |
3151 | * Conditions: | |
3152 | * initial waitq is locked | |
3153 | * ctx->thread is unlocked | |
3154 | * | |
3155 | * Notes: | |
3156 | * This may disable interrupts and early-out of the full DAG link walk by | |
3157 | * returning KERN_ALREADY_IN_SET. In this case, the returned thread has | |
3158 | * been removed from the waitq, it's waitq state has been reset, and the | |
3159 | * caller is responsible to call splx() with the returned interrupt state | |
3160 | * in ctx->spl. | |
3161 | */ | |
3162 | static int waitq_select_thread_cb(struct waitq *waitq, void *ctx, | |
3163 | struct setid_link *link) | |
3164 | { | |
3165 | struct select_thread_ctx *stctx = (struct select_thread_ctx *)ctx; | |
3166 | struct waitq_set *wqset; | |
3167 | ||
3168 | (void)waitq; | |
3169 | ||
3170 | thread_t thread = stctx->thread; | |
3171 | event64_t event = stctx->event; | |
3172 | ||
3173 | if (sl_type(link) != SLT_WQS) | |
3174 | return WQ_ITERATE_CONTINUE; | |
3175 | ||
3176 | wqset = link->sl_wqs.sl_set; | |
3177 | ||
3178 | if (!waitq_irq_safe(waitq) && waitq_irq_safe(&wqset->wqset_q)) { | |
3179 | *(stctx->spl) = splsched(); | |
3180 | waitq_set_lock(wqset); | |
3181 | thread_lock(thread); | |
3182 | } else { | |
3183 | waitq_set_lock(wqset); | |
3184 | *(stctx->spl) = splsched(); | |
3185 | thread_lock(thread); | |
3186 | } | |
3187 | ||
3188 | if ((thread->waitq == &wqset->wqset_q) | |
3189 | && (thread->wait_event == event)) { | |
3190 | remqueue(&thread->links); | |
3191 | thread_clear_waitq_state(thread); | |
3192 | /* | |
3193 | * thread still locked, | |
3194 | * return non-zero to break out of WQS walk | |
3195 | */ | |
3196 | waitq_set_unlock(wqset); | |
3197 | return WQ_ITERATE_FOUND; | |
3198 | } | |
3199 | ||
3200 | thread_unlock(thread); | |
3201 | waitq_set_unlock(wqset); | |
3202 | splx(*(stctx->spl)); | |
3203 | ||
3204 | return WQ_ITERATE_CONTINUE; | |
3205 | } | |
3206 | ||
3207 | /** | |
3208 | * returns KERN_SUCCESS and locks 'thread' if-and-only-if 'thread' is waiting | |
3209 | * on 'waitq' (or any set to which waitq belongs) for 'event' | |
3210 | * | |
3211 | * Conditions: | |
3212 | * 'waitq' is locked | |
3213 | * 'thread' is unlocked | |
3214 | */ | |
3215 | static kern_return_t waitq_select_thread_locked(struct waitq *waitq, | |
3216 | event64_t event, | |
3217 | thread_t thread, spl_t *spl) | |
3218 | { | |
3219 | struct setid_link *link; | |
3220 | struct select_thread_ctx ctx; | |
3221 | kern_return_t kr; | |
3222 | ||
3223 | *spl = splsched(); | |
3224 | thread_lock(thread); | |
3225 | ||
3226 | if ((thread->waitq == waitq) && (thread->wait_event == event)) { | |
3227 | remqueue(&thread->links); | |
3228 | thread_clear_waitq_state(thread); | |
3229 | /* thread still locked */ | |
3230 | return KERN_SUCCESS; | |
3231 | } | |
3232 | ||
3233 | thread_unlock(thread); | |
3234 | splx(*spl); | |
3235 | ||
3236 | if (!waitq->waitq_set_id) | |
3237 | return KERN_NOT_WAITING; | |
3238 | ||
3239 | /* check to see if the set ID for this wait queue is valid */ | |
3240 | link = lt_get_link(waitq->waitq_set_id); | |
3241 | if (!link) { | |
3242 | /* the waitq to which this set belonged, has been invalidated */ | |
3243 | waitq->waitq_set_id = 0; | |
3244 | return KERN_NOT_WAITING; | |
3245 | } | |
3246 | ||
3247 | /* | |
3248 | * The thread may be waiting on a wait queue set to which | |
3249 | * the input 'waitq' belongs. Go look for the thread in | |
3250 | * all wait queue sets. If it's there, we'll remove it | |
3251 | * because it's equivalent to waiting directly on the input waitq. | |
3252 | */ | |
3253 | ctx.thread = thread; | |
3254 | ctx.event = event; | |
3255 | ctx.spl = spl; | |
3256 | kr = walk_setid_links(LINK_WALK_FULL_DAG, waitq, waitq->waitq_set_id, | |
3257 | SLT_WQS, (void *)&ctx, waitq_select_thread_cb); | |
3258 | ||
3259 | lt_put_link(link); | |
3260 | ||
3261 | /* we found a thread, return success */ | |
3262 | if (kr == WQ_ITERATE_FOUND) | |
3263 | return KERN_SUCCESS; | |
3264 | ||
3265 | return KERN_NOT_WAITING; | |
3266 | } | |
3267 | ||
3268 | static int prepost_exists_cb(struct waitq_set __unused *wqset, | |
3269 | void __unused *ctx, | |
3270 | struct wq_prepost __unused *wqp, | |
3271 | struct waitq __unused *waitq) | |
3272 | { | |
3273 | /* if we get here, then we know that there is a valid prepost object! */ | |
3274 | return WQ_ITERATE_FOUND; | |
3275 | } | |
3276 | ||
3277 | /** | |
3278 | * declare a thread's intent to wait on 'waitq' for 'wait_event' | |
3279 | * | |
3280 | * Conditions: | |
3281 | * 'waitq' is locked | |
3282 | * 'thread' is locked | |
3283 | */ | |
3284 | wait_result_t waitq_assert_wait64_locked(struct waitq *waitq, | |
3285 | event64_t wait_event, | |
3286 | wait_interrupt_t interruptible, | |
3287 | wait_timeout_urgency_t urgency, | |
3288 | uint64_t deadline, | |
3289 | uint64_t leeway, | |
3290 | thread_t thread) | |
3291 | { | |
3292 | wait_result_t wait_result; | |
3293 | int realtime = 0; | |
3294 | ||
3295 | /* | |
3296 | * Warning: Do _not_ place debugging print statements here. | |
3297 | * The thread is locked! | |
3298 | */ | |
3299 | ||
3300 | if (thread->waitq != NULL) | |
3301 | panic("thread already waiting on %p", thread->waitq); | |
3302 | ||
3303 | if (waitq_is_set(waitq)) { | |
3304 | struct waitq_set *wqset = (struct waitq_set *)waitq; | |
3305 | /* | |
3306 | * early-out if the thread is waiting on a wait queue set | |
3307 | * that has already been pre-posted. | |
3308 | */ | |
3309 | if (wait_event == NO_EVENT64 && waitq_set_maybe_preposted(wqset)) { | |
3310 | int ret; | |
3311 | /* | |
3312 | * Run through the list of potential preposts. Because | |
3313 | * this is a hot path, we short-circuit the iteration | |
3314 | * if we find just one prepost object. | |
3315 | */ | |
3316 | ret = wq_prepost_foreach_locked(wqset, NULL, | |
3317 | prepost_exists_cb); | |
3318 | if (ret == WQ_ITERATE_FOUND) { | |
3319 | thread->wait_result = THREAD_AWAKENED; | |
3320 | return THREAD_AWAKENED; | |
3321 | } | |
3322 | } | |
3323 | } | |
3324 | ||
3325 | /* | |
3326 | * Realtime threads get priority for wait queue placements. | |
3327 | * This allows wait_queue_wakeup_one to prefer a waiting | |
3328 | * realtime thread, similar in principle to performing | |
3329 | * a wait_queue_wakeup_all and allowing scheduler prioritization | |
3330 | * to run the realtime thread, but without causing the | |
3331 | * lock contention of that scenario. | |
3332 | */ | |
3333 | if (thread->sched_pri >= BASEPRI_REALTIME) | |
3334 | realtime = 1; | |
3335 | ||
3336 | /* | |
3337 | * This is the extent to which we currently take scheduling attributes | |
3338 | * into account. If the thread is vm priviledged, we stick it at | |
3339 | * the front of the queue. Later, these queues will honor the policy | |
3340 | * value set at waitq_init time. | |
3341 | */ | |
3342 | wait_result = thread_mark_wait_locked(thread, interruptible); | |
3343 | /* thread->wait_result has been set */ | |
3344 | if (wait_result == THREAD_WAITING) { | |
3345 | if (!waitq->waitq_fifo | |
3346 | || (thread->options & TH_OPT_VMPRIV) || realtime) | |
3347 | enqueue_head(&waitq->waitq_queue, &thread->links); | |
3348 | else | |
3349 | enqueue_tail(&waitq->waitq_queue, &thread->links); | |
3350 | ||
3351 | thread->wait_event = wait_event; | |
3352 | thread->waitq = waitq; | |
3353 | ||
3354 | if (deadline != 0) { | |
3355 | boolean_t act; | |
3356 | act = timer_call_enter_with_leeway(&thread->wait_timer, | |
3357 | NULL, | |
3358 | deadline, leeway, | |
3359 | urgency, FALSE); | |
3360 | if (!act) | |
3361 | thread->wait_timer_active++; | |
3362 | thread->wait_timer_is_set = TRUE; | |
3363 | } | |
3364 | ||
3365 | if (waitq_is_global(waitq)) | |
3366 | waitq->waitq_eventmask = waitq->waitq_eventmask | |
3367 | | _CAST_TO_EVENT_MASK(wait_event); | |
3368 | ||
3369 | waitq_stats_count_wait(waitq); | |
3370 | } | |
3371 | ||
3372 | return wait_result; | |
3373 | } | |
3374 | ||
3375 | /** | |
3376 | * remove 'thread' from its current blocking state on 'waitq' | |
3377 | * | |
3378 | * Conditions: | |
3379 | * 'waitq' is locked | |
3380 | * 'thread' is locked | |
3381 | * | |
3382 | * Notes: | |
3383 | * This function is primarily used by clear_wait_internal in | |
3384 | * sched_prim.c from the thread timer wakeup path | |
3385 | * (i.e. the thread was waiting on 'waitq' with a timeout that expired) | |
3386 | */ | |
3387 | void waitq_pull_thread_locked(struct waitq *waitq, thread_t thread) | |
3388 | { | |
3389 | (void)waitq; | |
3390 | assert(thread->waitq == waitq); | |
3391 | ||
3392 | remqueue(&thread->links); | |
3393 | thread_clear_waitq_state(thread); | |
3394 | waitq_stats_count_clear_wakeup(waitq); | |
3395 | ||
3396 | /* clear the global event mask if this was the last thread there! */ | |
3397 | if (waitq_is_global(waitq) && queue_empty(&waitq->waitq_queue)) | |
3398 | waitq->waitq_eventmask = 0; | |
3399 | } | |
3400 | ||
3401 | ||
3402 | static __inline__ | |
3403 | void maybe_adjust_thread_pri(thread_t thread, int priority) { | |
3404 | if (thread->sched_pri < priority) { | |
3405 | if (priority <= MAXPRI) { | |
3406 | set_sched_pri(thread, priority); | |
3407 | ||
3408 | thread->was_promoted_on_wakeup = 1; | |
3409 | thread->sched_flags |= TH_SFLAG_PROMOTED; | |
3410 | } | |
3411 | return; | |
3412 | } | |
3413 | ||
3414 | /* | |
3415 | * If the caller is requesting the waitq subsystem to promote the | |
3416 | * priority of the awoken thread, then boost the thread's priority to | |
3417 | * the default WAITQ_BOOST_PRIORITY (if it's not already equal or | |
3418 | * higher priority). This boost must be removed via a call to | |
3419 | * waitq_clear_promotion_locked. | |
3420 | */ | |
3421 | if (priority == WAITQ_PROMOTE_PRIORITY && | |
3422 | (thread->sched_pri < WAITQ_BOOST_PRIORITY || | |
3423 | !(thread->sched_flags & TH_SFLAG_WAITQ_PROMOTED))) { | |
3424 | ||
3425 | KERNEL_DEBUG_CONSTANT(MACHDBG_CODE(DBG_MACH_SCHED, MACH_WAITQ_PROMOTE) | DBG_FUNC_NONE, | |
3426 | (uintptr_t)thread_tid(thread), | |
3427 | thread->sched_pri, thread->base_pri, | |
3428 | WAITQ_BOOST_PRIORITY, 0); | |
3429 | thread->sched_flags |= TH_SFLAG_WAITQ_PROMOTED; | |
3430 | if (thread->sched_pri < WAITQ_BOOST_PRIORITY) | |
3431 | set_sched_pri(thread, WAITQ_BOOST_PRIORITY); | |
3432 | } | |
3433 | } | |
3434 | ||
3435 | /** | |
3436 | * Clear a thread's waitq priority promotion state and the waitq's boost flag | |
3437 | * | |
3438 | * This function will always clear the waitq's 'waitq_boost' flag. If the | |
3439 | * 'thread' parameter is non-null, the this function will also check the | |
3440 | * priority promotion (boost) state of that thread. If this thread was boosted | |
3441 | * (by having been awoken from a boosting waitq), then this boost state is | |
3442 | * cleared. This function is to be paired with waitq_enable_promote_locked. | |
3443 | */ | |
3444 | void waitq_clear_promotion_locked(struct waitq *waitq, thread_t thread) | |
3445 | { | |
3446 | spl_t s; | |
3447 | ||
3448 | assert(waitq_held(waitq)); | |
3449 | if (thread == THREAD_NULL) | |
3450 | return; | |
3451 | ||
3452 | if (!waitq_irq_safe(waitq)) | |
3453 | s = splsched(); | |
3454 | thread_lock(thread); | |
3455 | ||
3456 | if (thread->sched_flags & TH_SFLAG_WAITQ_PROMOTED) { | |
3457 | thread->sched_flags &= ~TH_SFLAG_WAITQ_PROMOTED; | |
3458 | ||
3459 | if (thread->sched_flags & TH_SFLAG_PROMOTED_MASK) { | |
3460 | /* it still has other promotions (mutex/rw_lock) */ | |
3461 | } else if (thread->sched_flags & TH_SFLAG_DEPRESSED_MASK) { | |
3462 | KERNEL_DEBUG_CONSTANT(MACHDBG_CODE(DBG_MACH_SCHED, MACH_WAITQ_DEMOTE) | DBG_FUNC_NONE, | |
3463 | (uintptr_t)thread_tid(thread), | |
3464 | thread->sched_pri, | |
3465 | thread->base_pri, | |
3466 | DEPRESSPRI, 0); | |
3467 | set_sched_pri(thread, DEPRESSPRI); | |
3468 | } else { | |
3469 | KERNEL_DEBUG_CONSTANT(MACHDBG_CODE(DBG_MACH_SCHED, MACH_WAITQ_DEMOTE) | DBG_FUNC_NONE, | |
3470 | (uintptr_t)thread_tid(thread), | |
3471 | thread->sched_pri, | |
3472 | thread->base_pri, | |
3473 | thread->base_pri, 0); | |
3474 | thread_recompute_sched_pri(thread, FALSE); | |
3475 | } | |
3476 | } | |
3477 | ||
3478 | thread_unlock(thread); | |
3479 | if (!waitq_irq_safe(waitq)) | |
3480 | splx(s); | |
3481 | } | |
3482 | ||
3483 | /** | |
3484 | * wakeup all threads waiting on 'waitq' for 'wake_event' | |
3485 | * | |
3486 | * Conditions: | |
3487 | * 'waitq' is locked | |
3488 | * | |
3489 | * Notes: | |
3490 | * May temporarily disable and re-enable interrupts | |
3491 | * and re-adjust thread priority of each awoken thread. | |
3492 | * | |
3493 | * If the input 'lock_state' == WAITQ_UNLOCK then the waitq will have | |
3494 | * been unlocked before calling thread_go() on any returned threads, and | |
3495 | * is guaranteed to be unlocked upon function return. | |
3496 | */ | |
3497 | kern_return_t waitq_wakeup64_all_locked(struct waitq *waitq, | |
3498 | event64_t wake_event, | |
3499 | wait_result_t result, | |
3500 | uint64_t *reserved_preposts, | |
3501 | int priority, | |
3502 | waitq_lock_state_t lock_state) | |
3503 | { | |
3504 | kern_return_t ret; | |
3505 | thread_t thread; | |
3506 | spl_t th_spl; | |
3507 | int nthreads; | |
3508 | queue_head_t wakeup_queue; | |
3509 | ||
3510 | assert(waitq_held(waitq)); | |
3511 | queue_init(&wakeup_queue); | |
3512 | ||
3513 | nthreads = waitq_select_n_locked(waitq, wake_event, NULL, NULL, | |
3514 | reserved_preposts, | |
3515 | &wakeup_queue, -1, &th_spl); | |
3516 | ||
3517 | /* set each thread running */ | |
3518 | ret = KERN_NOT_WAITING; | |
3519 | ||
3520 | #if CONFIG_WAITQ_STATS | |
3521 | qe_foreach_element(thread, &wakeup_queue, links) | |
3522 | waitq_stats_count_wakeup(waitq); | |
3523 | #endif | |
3524 | if (lock_state == WAITQ_UNLOCK) | |
3525 | waitq_unlock(waitq); | |
3526 | ||
3527 | qe_foreach_element_safe(thread, &wakeup_queue, links) { | |
3528 | remqueue(&thread->links); | |
3529 | maybe_adjust_thread_pri(thread, priority); | |
3530 | ret = thread_go(thread, result); | |
3531 | assert(ret == KERN_SUCCESS); | |
3532 | thread_unlock(thread); | |
3533 | } | |
3534 | if (nthreads > 0) | |
3535 | splx(th_spl); | |
3536 | else | |
3537 | waitq_stats_count_fail(waitq); | |
3538 | ||
3539 | return ret; | |
3540 | } | |
3541 | ||
3542 | /** | |
3543 | * wakeup one thread waiting on 'waitq' for 'wake_event' | |
3544 | * | |
3545 | * Conditions: | |
3546 | * 'waitq' is locked | |
3547 | * | |
3548 | * Notes: | |
3549 | * May temporarily disable and re-enable interrupts. | |
3550 | */ | |
3551 | kern_return_t waitq_wakeup64_one_locked(struct waitq *waitq, | |
3552 | event64_t wake_event, | |
3553 | wait_result_t result, | |
3554 | uint64_t *reserved_preposts, | |
3555 | int priority, | |
3556 | waitq_lock_state_t lock_state) | |
3557 | { | |
3558 | thread_t thread; | |
3559 | spl_t th_spl; | |
3560 | ||
3561 | assert(waitq_held(waitq)); | |
3562 | ||
3563 | thread = waitq_select_one_locked(waitq, wake_event, | |
3564 | reserved_preposts, | |
3565 | priority, &th_spl); | |
3566 | ||
3567 | if (thread != THREAD_NULL) | |
3568 | waitq_stats_count_wakeup(waitq); | |
3569 | else | |
3570 | waitq_stats_count_fail(waitq); | |
3571 | ||
3572 | if (lock_state == WAITQ_UNLOCK) | |
3573 | waitq_unlock(waitq); | |
3574 | ||
3575 | if (thread != THREAD_NULL) { | |
3576 | maybe_adjust_thread_pri(thread, priority); | |
3577 | kern_return_t ret = thread_go(thread, result); | |
3578 | assert(ret == KERN_SUCCESS); | |
3579 | thread_unlock(thread); | |
3580 | splx(th_spl); | |
3581 | return ret; | |
3582 | } | |
3583 | ||
3584 | return KERN_NOT_WAITING; | |
3585 | } | |
3586 | ||
3587 | /** | |
3588 | * wakeup one thread waiting on 'waitq' for 'wake_event' | |
3589 | * | |
3590 | * Conditions: | |
3591 | * 'waitq' is locked | |
3592 | * | |
3593 | * Returns: | |
3594 | * A locked, runnable thread. | |
3595 | * If return value is non-NULL, interrupts have also | |
3596 | * been disabled, and the caller is responsible to call | |
3597 | * splx() with the returned '*spl' value. | |
3598 | */ | |
3599 | thread_t waitq_wakeup64_identity_locked(struct waitq *waitq, | |
3600 | event64_t wake_event, | |
3601 | wait_result_t result, | |
3602 | spl_t *spl, | |
3603 | uint64_t *reserved_preposts, | |
3604 | waitq_lock_state_t lock_state) | |
3605 | { | |
3606 | thread_t thread; | |
3607 | ||
3608 | assert(waitq_held(waitq)); | |
3609 | ||
3610 | thread = waitq_select_one_locked(waitq, wake_event, | |
3611 | reserved_preposts, | |
3612 | WAITQ_ALL_PRIORITIES, spl); | |
3613 | ||
3614 | if (thread != THREAD_NULL) | |
3615 | waitq_stats_count_wakeup(waitq); | |
3616 | else | |
3617 | waitq_stats_count_fail(waitq); | |
3618 | ||
3619 | if (lock_state == WAITQ_UNLOCK) | |
3620 | waitq_unlock(waitq); | |
3621 | ||
3622 | if (thread != THREAD_NULL) { | |
3623 | kern_return_t __assert_only ret; | |
3624 | ret = thread_go(thread, result); | |
3625 | assert(ret == KERN_SUCCESS); | |
3626 | } | |
3627 | ||
3628 | return thread; /* locked if not NULL (caller responsible for spl) */ | |
3629 | } | |
3630 | ||
3631 | /** | |
3632 | * wakeup a specific thread iff it's waiting on 'waitq' for 'wake_event' | |
3633 | * | |
3634 | * Conditions: | |
3635 | * 'waitq' is locked | |
3636 | * 'thread' is unlocked | |
3637 | * | |
3638 | * Notes: | |
3639 | * May temporarily disable and re-enable interrupts | |
3640 | * | |
3641 | * If the input lock_state == WAITQ_UNLOCK then the waitq will have been | |
3642 | * unlocked before calling thread_go() if 'thread' is to be awoken, and | |
3643 | * is guaranteed to be unlocked upon function return. | |
3644 | */ | |
3645 | kern_return_t waitq_wakeup64_thread_locked(struct waitq *waitq, | |
3646 | event64_t wake_event, | |
3647 | thread_t thread, | |
3648 | wait_result_t result, | |
3649 | waitq_lock_state_t lock_state) | |
3650 | { | |
3651 | kern_return_t ret; | |
3652 | spl_t th_spl; | |
3653 | ||
3654 | assert(waitq_held(waitq)); | |
3655 | ||
3656 | /* | |
3657 | * See if the thread was still waiting there. If so, it got | |
3658 | * dequeued and returned locked. | |
3659 | */ | |
3660 | ret = waitq_select_thread_locked(waitq, wake_event, thread, &th_spl); | |
3661 | ||
3662 | if (ret == KERN_SUCCESS) | |
3663 | waitq_stats_count_wakeup(waitq); | |
3664 | else | |
3665 | waitq_stats_count_fail(waitq); | |
3666 | ||
3667 | if (lock_state == WAITQ_UNLOCK) | |
3668 | waitq_unlock(waitq); | |
3669 | ||
3670 | if (ret != KERN_SUCCESS) | |
3671 | return KERN_NOT_WAITING; | |
3672 | ||
3673 | ret = thread_go(thread, result); | |
3674 | assert(ret == KERN_SUCCESS); | |
3675 | thread_unlock(thread); | |
3676 | splx(th_spl); | |
3677 | ||
3678 | return ret; | |
3679 | } | |
3680 | ||
3681 | ||
3682 | ||
3683 | /* ---------------------------------------------------------------------- | |
3684 | * | |
3685 | * In-Kernel API | |
3686 | * | |
3687 | * ---------------------------------------------------------------------- */ | |
3688 | ||
3689 | /** | |
3690 | * initialize a waitq object | |
3691 | */ | |
3692 | kern_return_t waitq_init(struct waitq *waitq, int policy) | |
3693 | { | |
3694 | assert(waitq != NULL); | |
3695 | ||
3696 | /* only FIFO and LIFO for now */ | |
3697 | if ((policy & SYNC_POLICY_FIXED_PRIORITY) != 0) | |
3698 | return KERN_INVALID_ARGUMENT; | |
3699 | ||
3700 | waitq->waitq_fifo = ((policy & SYNC_POLICY_REVERSED) == 0); | |
3701 | waitq->waitq_irq = !!(policy & SYNC_POLICY_DISABLE_IRQ); | |
3702 | waitq->waitq_prepost = 0; | |
3703 | waitq->waitq_type = WQT_QUEUE; | |
3704 | waitq->waitq_eventmask = 0; | |
3705 | ||
3706 | waitq->waitq_set_id = 0; | |
3707 | waitq->waitq_prepost_id = 0; | |
3708 | ||
3709 | hw_lock_init(&waitq->waitq_interlock); | |
3710 | queue_init(&waitq->waitq_queue); | |
3711 | ||
3712 | return KERN_SUCCESS; | |
3713 | } | |
3714 | ||
3715 | struct wq_unlink_ctx { | |
3716 | struct waitq *unlink_wq; | |
3717 | struct waitq_set *unlink_wqset; | |
3718 | }; | |
3719 | ||
3720 | static int waitq_unlink_prepost_cb(struct waitq_set __unused *wqset, void *ctx, | |
3721 | struct wq_prepost *wqp, struct waitq *waitq); | |
3722 | ||
3723 | /** | |
3724 | * walk_setid_links callback to invalidate 'link' parameter | |
3725 | * | |
3726 | * Conditions: | |
3727 | * Called from walk_setid_links. | |
3728 | * Note that unlink other callbacks, this one make no assumptions about | |
3729 | * the 'waitq' parameter, specifically it does not have to be locked or | |
3730 | * even valid. | |
3731 | */ | |
3732 | static int waitq_unlink_all_cb(struct waitq *waitq, void *ctx, | |
3733 | struct setid_link *link) | |
3734 | { | |
3735 | (void)waitq; | |
3736 | (void)ctx; | |
3737 | if (sl_type(link) == SLT_LINK && sl_is_valid(link)) | |
3738 | lt_invalidate(link); | |
3739 | ||
3740 | if (sl_type(link) == SLT_WQS) { | |
3741 | struct waitq_set *wqset; | |
3742 | int do_spl = 0; | |
3743 | spl_t spl; | |
3744 | struct wq_unlink_ctx ulctx; | |
3745 | ||
3746 | /* | |
3747 | * When destroying the waitq, take the time to clear out any | |
3748 | * preposts it may have made. This could potentially save time | |
3749 | * on the IPC send path which would otherwise have to iterate | |
3750 | * over lots of dead port preposts. | |
3751 | */ | |
3752 | if (waitq->waitq_prepost_id == 0) | |
3753 | goto out; | |
3754 | ||
3755 | wqset = link->sl_wqs.sl_set; | |
3756 | assert(wqset != NULL); | |
3757 | ||
3758 | if (waitq_set_is_valid(wqset) && | |
3759 | waitq_irq_safe(&wqset->wqset_q)) { | |
3760 | spl = splsched(); | |
3761 | do_spl = 1; | |
3762 | } | |
3763 | waitq_set_lock(wqset); | |
3764 | ||
3765 | if (!waitq_set_is_valid(wqset)) { | |
3766 | /* someone raced us to teardown */ | |
3767 | goto out_unlock; | |
3768 | } | |
3769 | if (!waitq_set_maybe_preposted(wqset)) | |
3770 | goto out_unlock; | |
3771 | ||
3772 | ulctx.unlink_wq = waitq; | |
3773 | ulctx.unlink_wqset = wqset; | |
3774 | (void)wq_prepost_iterate(wqset->wqset_prepost_id, &ulctx, | |
3775 | waitq_unlink_prepost_cb); | |
3776 | out_unlock: | |
3777 | waitq_set_unlock(wqset); | |
3778 | if (do_spl) | |
3779 | splx(spl); | |
3780 | } | |
3781 | ||
3782 | out: | |
3783 | return WQ_ITERATE_CONTINUE; | |
3784 | } | |
3785 | ||
3786 | ||
3787 | /** | |
3788 | * cleanup any link/prepost table resources associated with a waitq | |
3789 | */ | |
3790 | void waitq_deinit(struct waitq *waitq) | |
3791 | { | |
3792 | uint64_t setid = 0; | |
3793 | spl_t s; | |
3794 | ||
3795 | if (!waitq_valid(waitq)) | |
3796 | return; | |
3797 | ||
3798 | if (waitq_irq_safe(waitq)) | |
3799 | s = splsched(); | |
3800 | waitq_lock(waitq); | |
3801 | if (!waitq_valid(waitq)) | |
3802 | goto out; | |
3803 | ||
3804 | waitq_unlink_all_locked(waitq, &setid, &s, NULL); | |
3805 | waitq->waitq_type = WQT_INVALID; | |
3806 | assert(queue_empty(&waitq->waitq_queue)); | |
3807 | ||
3808 | out: | |
3809 | waitq_unlock(waitq); | |
3810 | if (waitq_irq_safe(waitq)) | |
3811 | splx(s); | |
3812 | ||
3813 | if (setid) | |
3814 | (void)walk_setid_links(LINK_WALK_ONE_LEVEL, waitq, setid, | |
3815 | SLT_ALL, NULL, waitq_unlink_all_cb); | |
3816 | } | |
3817 | ||
3818 | ||
3819 | /** | |
3820 | * invalidate the given wq_prepost object | |
3821 | * | |
3822 | * Conditions: | |
3823 | * Called from wq_prepost_iterate (_not_ from wq_prepost_foreach_locked!) | |
3824 | */ | |
3825 | static int wqset_clear_prepost_chain_cb(struct waitq_set __unused *wqset, | |
3826 | void __unused *ctx, | |
3827 | struct wq_prepost *wqp, | |
3828 | struct waitq __unused *waitq) | |
3829 | { | |
3830 | if (wqp_type(wqp) == WQP_POST) | |
3831 | wq_prepost_invalidate(wqp); | |
3832 | return WQ_ITERATE_CONTINUE; | |
3833 | } | |
3834 | ||
3835 | ||
3836 | /** | |
3837 | * allocate and initialize a waitq set object | |
3838 | * | |
3839 | * Conditions: | |
3840 | * may block | |
3841 | * | |
3842 | * Returns: | |
3843 | * allocated / initialized waitq_set object | |
3844 | * NULL on failure | |
3845 | */ | |
3846 | struct waitq_set *waitq_set_alloc(int policy) | |
3847 | { | |
3848 | struct waitq_set *wqset; | |
3849 | ||
3850 | wqset = (struct waitq_set *)zalloc(waitq_set_zone); | |
3851 | if (!wqset) | |
3852 | panic("Can't allocate a new waitq set from zone %p", waitq_set_zone); | |
3853 | ||
3854 | kern_return_t ret; | |
3855 | ret = waitq_set_init(wqset, policy, NULL); | |
3856 | if (ret != KERN_SUCCESS) { | |
3857 | zfree(waitq_set_zone, wqset); | |
3858 | wqset = NULL; | |
3859 | } | |
3860 | ||
3861 | return wqset; | |
3862 | } | |
3863 | ||
3864 | /** | |
3865 | * initialize a waitq set object | |
3866 | * | |
3867 | * Conditions: | |
3868 | * may (rarely) block if link table needs to grow, and | |
3869 | * no 'reserved_link' object is passed. | |
3870 | */ | |
3871 | kern_return_t waitq_set_init(struct waitq_set *wqset, | |
3872 | int policy, uint64_t *reserved_link) | |
3873 | { | |
3874 | struct setid_link *link; | |
3875 | kern_return_t ret; | |
3876 | ||
3877 | memset(wqset, 0, sizeof(*wqset)); | |
3878 | ||
3879 | ret = waitq_init(&wqset->wqset_q, policy); | |
3880 | if (ret != KERN_SUCCESS) | |
3881 | return ret; | |
3882 | ||
3883 | wqset->wqset_q.waitq_type = WQT_SET; | |
3884 | if (policy & SYNC_POLICY_PREPOST) | |
3885 | wqset->wqset_q.waitq_prepost = 1; | |
3886 | else | |
3887 | wqset->wqset_q.waitq_prepost = 0; | |
3888 | ||
3889 | if (reserved_link && *reserved_link != 0) { | |
3890 | link = lt_get_reserved(*reserved_link, SLT_WQS); | |
3891 | /* always consume the caller's reference */ | |
3892 | *reserved_link = 0; | |
3893 | } else { | |
3894 | link = lt_alloc_link(SLT_WQS); | |
3895 | } | |
3896 | if (!link) | |
3897 | panic("Can't allocate link object for waitq set: %p", wqset); | |
3898 | ||
3899 | link->sl_wqs.sl_set = wqset; | |
3900 | sl_set_valid(link); | |
3901 | ||
3902 | wqset->wqset_id = link->sl_set_id.id; | |
3903 | wqset->wqset_prepost_id = 0; | |
3904 | lt_put_link(link); | |
3905 | ||
3906 | return KERN_SUCCESS; | |
3907 | } | |
3908 | ||
3909 | /** | |
3910 | * clear out / release any resources associated with a waitq set | |
3911 | * | |
3912 | * Conditions: | |
3913 | * may block | |
3914 | * Note: | |
3915 | * This will render the waitq set invalid, and it must | |
3916 | * be re-initialized with waitq_set_init before it can be used again | |
3917 | */ | |
3918 | void waitq_set_deinit(struct waitq_set *wqset) | |
3919 | { | |
3920 | struct setid_link *link = NULL; | |
3921 | uint64_t set_id, set_links_id, prepost_id; | |
3922 | int do_spl = 0; | |
3923 | spl_t s; | |
3924 | ||
3925 | if (!waitqs_is_set(wqset)) | |
3926 | panic("trying to de-initialize an invalid wqset @%p", wqset); | |
3927 | ||
3928 | if (waitq_irq_safe(&wqset->wqset_q)) { | |
3929 | s = splsched(); | |
3930 | do_spl = 1; | |
3931 | } | |
3932 | waitq_set_lock(wqset); | |
3933 | ||
3934 | set_id = wqset->wqset_id; | |
3935 | ||
3936 | /* grab the set's link object */ | |
3937 | link = lt_get_link(set_id); | |
3938 | if (link) | |
3939 | lt_invalidate(link); | |
3940 | ||
3941 | /* someone raced us to deinit */ | |
3942 | if (!link || wqset->wqset_id != set_id || set_id != link->sl_set_id.id) { | |
3943 | if (link) | |
3944 | lt_put_link(link); | |
3945 | waitq_set_unlock(wqset); | |
3946 | if (do_spl) | |
3947 | splx(s); | |
3948 | return; | |
3949 | } | |
3950 | ||
3951 | /* every wait queue set should have a valid link object */ | |
3952 | assert(link != NULL && sl_type(link) == SLT_WQS); | |
3953 | ||
3954 | wqset->wqset_id = 0; | |
3955 | ||
3956 | wqset->wqset_q.waitq_type = WQT_INVALID; | |
3957 | wqset->wqset_q.waitq_fifo = 0; | |
3958 | wqset->wqset_q.waitq_prepost = 0; | |
3959 | /* don't clear the 'waitq_irq' bit: it's used in locking! */ | |
3960 | wqset->wqset_q.waitq_eventmask = 0; | |
3961 | ||
3962 | /* | |
3963 | * This set may have a lot of preposts, or may have been a member of | |
3964 | * many other sets. To minimize spinlock hold times, we clear out the | |
3965 | * waitq set data structure under the lock-hold, but don't clear any | |
3966 | * table objects. We keep handles to the prepost and set linkage | |
3967 | * objects and free those outside the critical section. | |
3968 | */ | |
3969 | prepost_id = wqset->wqset_prepost_id; | |
3970 | wqset->wqset_prepost_id = 0; | |
3971 | ||
3972 | set_links_id = 0; | |
3973 | waitq_unlink_all_locked(&wqset->wqset_q, &set_links_id, &s, NULL); | |
3974 | ||
3975 | waitq_set_unlock(wqset); | |
3976 | if (do_spl) | |
3977 | splx(s); | |
3978 | ||
3979 | /* | |
3980 | * walk_setid_links may race with us for access to the waitq set. | |
3981 | * If walk_setid_links has a reference to the set, then we should wait | |
3982 | * until the link's refcount goes to 1 (our reference) before we exit | |
3983 | * this function. That way we ensure that the waitq set memory will | |
3984 | * remain valid even though it's been cleared out. | |
3985 | */ | |
3986 | while (sl_refcnt(link) > 1) | |
3987 | delay(1); | |
3988 | lt_put_link(link); | |
3989 | ||
3990 | /* | |
3991 | * release all the set link objects | |
3992 | * (links to other sets to which this set was previously added) | |
3993 | */ | |
3994 | if (set_links_id) | |
3995 | (void)walk_setid_links(LINK_WALK_ONE_LEVEL, NULL, set_links_id, | |
3996 | SLT_ALL, NULL, waitq_unlink_all_cb); | |
3997 | ||
3998 | /* drop / unlink all the prepost table objects */ | |
3999 | (void)wq_prepost_iterate(prepost_id, NULL, wqset_clear_prepost_chain_cb); | |
4000 | } | |
4001 | ||
4002 | /** | |
4003 | * de-initialize and free an allocated waitq set object | |
4004 | * | |
4005 | * Conditions: | |
4006 | * may block | |
4007 | */ | |
4008 | kern_return_t waitq_set_free(struct waitq_set *wqset) | |
4009 | { | |
4010 | waitq_set_deinit(wqset); | |
4011 | ||
4012 | memset(wqset, 0, sizeof(*wqset)); | |
4013 | zfree(waitq_set_zone, wqset); | |
4014 | ||
4015 | return KERN_SUCCESS; | |
4016 | } | |
4017 | ||
4018 | #if defined(DEVLEOPMENT) || defined(DEBUG) | |
4019 | #if CONFIG_WAITQ_DEBUG | |
4020 | /** | |
4021 | * return the set ID of 'wqset' | |
4022 | */ | |
4023 | uint64_t wqset_id(struct waitq_set *wqset) | |
4024 | { | |
4025 | if (!wqset) | |
4026 | return 0; | |
4027 | ||
4028 | assert(waitqs_is_set(wqset)); | |
4029 | return wqset->wqset_id; | |
4030 | } | |
4031 | ||
4032 | /** | |
4033 | * returns a pointer to the waitq object embedded in 'wqset' | |
4034 | */ | |
4035 | struct waitq *wqset_waitq(struct waitq_set *wqset) | |
4036 | { | |
4037 | if (!wqset) | |
4038 | return NULL; | |
4039 | ||
4040 | assert(waitqs_is_set(wqset)); | |
4041 | ||
4042 | return &wqset->wqset_q; | |
4043 | } | |
4044 | #endif /* CONFIG_WAITQ_DEBUG */ | |
4045 | #endif /* DEVELOPMENT || DEBUG */ | |
4046 | ||
4047 | ||
4048 | /** | |
4049 | * clear all preposts originating from 'waitq' | |
4050 | * | |
4051 | * Conditions: | |
4052 | * 'waitq' locked | |
4053 | * may (rarely) spin waiting for another on-core thread to | |
4054 | * release the last reference to the waitq's prepost link object | |
4055 | * | |
4056 | * NOTE: | |
4057 | * If this function needs to spin, it will drop the waitq lock! | |
4058 | * The return value of the function indicates whether or not this | |
4059 | * happened: 1 == lock was dropped, 0 == lock held | |
4060 | */ | |
4061 | int waitq_clear_prepost_locked(struct waitq *waitq, spl_t *s) | |
4062 | { | |
4063 | struct wq_prepost *wqp; | |
4064 | int dropped_lock = 0; | |
4065 | ||
4066 | if (waitq->waitq_prepost_id == 0) | |
4067 | return 0; | |
4068 | ||
4069 | wqp = wq_prepost_get(waitq->waitq_prepost_id); | |
4070 | waitq->waitq_prepost_id = 0; | |
4071 | if (wqp) { | |
4072 | uint64_t wqp_id = wqp->wqp_prepostid.id; | |
4073 | wqdbg_v("invalidate prepost 0x%llx (refcnt:%d)", | |
4074 | wqp->wqp_prepostid.id, wqp_refcnt(wqp)); | |
4075 | wq_prepost_invalidate(wqp); | |
4076 | while (wqp_refcnt(wqp) > 1) { | |
4077 | int do_spl = waitq_irq_safe(waitq); | |
4078 | ||
4079 | /* | |
4080 | * Some other thread must have raced us to grab a link | |
4081 | * object reference before we invalidated it. This | |
4082 | * means that they are probably trying to access the | |
4083 | * waitq to which the prepost object points. We need | |
4084 | * to wait here until the other thread drops their | |
4085 | * reference. We know that no one else can get a | |
4086 | * reference (the object has been invalidated), and | |
4087 | * that prepost references are short-lived (dropped on | |
4088 | * a call to wq_prepost_put). We also know that no one | |
4089 | * blocks while holding a reference therefore the | |
4090 | * other reference holder must be on-core. We'll just | |
4091 | * sit and wait for the other reference to be dropped. | |
4092 | */ | |
4093 | disable_preemption(); | |
4094 | ||
4095 | waitq_unlock(waitq); | |
4096 | if (s && do_spl) | |
4097 | splx(*s); | |
4098 | dropped_lock = 1; | |
4099 | /* | |
4100 | * don't yield here, just spin and assume the other | |
4101 | * consumer is already on core... | |
4102 | */ | |
4103 | delay(1); | |
4104 | if (s && do_spl) | |
4105 | *s = splsched(); | |
4106 | waitq_lock(waitq); | |
4107 | ||
4108 | enable_preemption(); | |
4109 | } | |
4110 | if (wqp_refcnt(wqp) > 0 && wqp->wqp_prepostid.id == wqp_id) | |
4111 | wq_prepost_put(wqp); | |
4112 | } | |
4113 | ||
4114 | return dropped_lock; | |
4115 | } | |
4116 | ||
4117 | /** | |
4118 | * clear all preposts originating from 'waitq' | |
4119 | * | |
4120 | * Conditions: | |
4121 | * 'waitq' is not locked | |
4122 | * may disable and re-enable interrupts | |
4123 | */ | |
4124 | void waitq_clear_prepost(struct waitq *waitq) | |
4125 | { | |
4126 | spl_t s; | |
4127 | int do_spl = waitq_irq_safe(waitq); | |
4128 | ||
4129 | assert(waitq_valid(waitq)); | |
4130 | ||
4131 | if (do_spl) | |
4132 | s = splsched(); | |
4133 | waitq_lock(waitq); | |
4134 | /* it doesn't matter to us if the lock is dropped here */ | |
4135 | (void)waitq_clear_prepost_locked(waitq, &s); | |
4136 | waitq_unlock(waitq); | |
4137 | if (do_spl) | |
4138 | splx(s); | |
4139 | } | |
4140 | ||
4141 | /** | |
4142 | * return a the waitq's prepost object ID (allocate if necessary) | |
4143 | * | |
4144 | * Conditions: | |
4145 | * 'waitq' is unlocked | |
4146 | */ | |
4147 | uint64_t waitq_get_prepost_id(struct waitq *waitq) | |
4148 | { | |
4149 | struct wq_prepost *wqp; | |
4150 | uint64_t wqp_id = 0; | |
4151 | spl_t s; | |
4152 | ||
4153 | if (!waitq_valid(waitq)) | |
4154 | return 0; | |
4155 | ||
4156 | if (waitq_irq_safe(waitq)) | |
4157 | s = splsched(); | |
4158 | waitq_lock(waitq); | |
4159 | ||
4160 | if (!waitq_valid(waitq)) | |
4161 | goto out_unlock; | |
4162 | ||
4163 | if (waitq->waitq_prepost_id) { | |
4164 | wqp_id = waitq->waitq_prepost_id; | |
4165 | goto out_unlock; | |
4166 | } | |
4167 | ||
4168 | /* don't hold a spinlock while allocating a prepost object */ | |
4169 | waitq_unlock(waitq); | |
4170 | if (waitq_irq_safe(waitq)) | |
4171 | splx(s); | |
4172 | ||
4173 | wqp = wq_prepost_alloc(WQP_WQ, 1); | |
4174 | if (!wqp) | |
4175 | return 0; | |
4176 | ||
4177 | /* re-acquire the waitq lock */ | |
4178 | if (waitq_irq_safe(waitq)) | |
4179 | s = splsched(); | |
4180 | waitq_lock(waitq); | |
4181 | ||
4182 | if (!waitq_valid(waitq)) { | |
4183 | wq_prepost_put(wqp); | |
4184 | wqp_id = 0; | |
4185 | goto out_unlock; | |
4186 | } | |
4187 | ||
4188 | if (waitq->waitq_prepost_id) { | |
4189 | /* we were beat by someone else */ | |
4190 | wq_prepost_put(wqp); | |
4191 | wqp_id = waitq->waitq_prepost_id; | |
4192 | goto out_unlock; | |
4193 | } | |
4194 | ||
4195 | wqp->wqp_wq.wqp_wq_ptr = waitq; | |
4196 | ||
4197 | wqp_set_valid(wqp); | |
4198 | wqp_id = wqp->wqp_prepostid.id; | |
4199 | waitq->waitq_prepost_id = wqp_id; | |
4200 | ||
4201 | wq_prepost_put(wqp); | |
4202 | ||
4203 | out_unlock: | |
4204 | waitq_unlock(waitq); | |
4205 | if (waitq_irq_safe(waitq)) | |
4206 | splx(s); | |
4207 | ||
4208 | return wqp_id; | |
4209 | } | |
4210 | ||
4211 | ||
4212 | static int waitq_inset_cb(struct waitq *waitq, void *ctx, struct setid_link *link) | |
4213 | { | |
4214 | uint64_t setid = *(uint64_t *)ctx; | |
4215 | int ltype = sl_type(link); | |
4216 | (void)waitq; | |
4217 | if (ltype == SLT_WQS && link->sl_set_id.id == setid) { | |
4218 | wqdbg_v(" waitq already in set 0x%llx", setid); | |
4219 | return WQ_ITERATE_FOUND; | |
4220 | } else if (ltype == SLT_LINK) { | |
4221 | /* | |
4222 | * break out early if we see a link that points to the setid | |
4223 | * in question. This saves us a step in the | |
4224 | * iteration/recursion | |
4225 | */ | |
4226 | wqdbg_v(" waitq already in set 0x%llx (SLT_LINK)", setid); | |
4227 | if (link->sl_link.sl_left_setid == setid || | |
4228 | link->sl_link.sl_right_setid == setid) | |
4229 | return WQ_ITERATE_FOUND; | |
4230 | } | |
4231 | ||
4232 | return WQ_ITERATE_CONTINUE; | |
4233 | } | |
4234 | ||
4235 | /** | |
4236 | * determine if 'waitq' is a member of 'wqset' | |
4237 | * | |
4238 | * Conditions: | |
4239 | * neither 'waitq' nor 'wqset' is not locked | |
4240 | * may disable and re-enable interrupts while locking 'waitq' | |
4241 | */ | |
4242 | boolean_t waitq_member(struct waitq *waitq, struct waitq_set *wqset) | |
4243 | { | |
4244 | kern_return_t kr = WQ_ITERATE_SUCCESS; | |
4245 | uint64_t setid; | |
4246 | spl_t s; | |
4247 | ||
4248 | if (!waitq_valid(waitq)) | |
4249 | panic("Invalid waitq: %p", waitq); | |
4250 | ||
4251 | if (!waitqs_is_set(wqset)) | |
4252 | return FALSE; | |
4253 | ||
4254 | if (waitq_irq_safe(waitq)) | |
4255 | s = splsched(); | |
4256 | waitq_lock(waitq); | |
4257 | ||
4258 | setid = wqset->wqset_id; | |
4259 | if (!setid) | |
4260 | goto out_unlock; | |
4261 | ||
4262 | /* fast path: most waitqs are members of only 1 set */ | |
4263 | if (waitq->waitq_set_id == setid) { | |
4264 | waitq_unlock(waitq); | |
4265 | if (waitq_irq_safe(waitq)) | |
4266 | splx(s); | |
4267 | return TRUE; | |
4268 | } | |
4269 | ||
4270 | /* walk the link table and look for the Set ID of wqset */ | |
4271 | kr = walk_setid_links(LINK_WALK_ONE_LEVEL, waitq, waitq->waitq_set_id, | |
4272 | SLT_ALL, (void *)&setid, waitq_inset_cb); | |
4273 | ||
4274 | out_unlock: | |
4275 | waitq_unlock(waitq); | |
4276 | if (waitq_irq_safe(waitq)) | |
4277 | splx(s); | |
4278 | ||
4279 | if (kr == WQ_ITERATE_FOUND) | |
4280 | return TRUE; | |
4281 | return FALSE; | |
4282 | } | |
4283 | ||
4284 | /** | |
4285 | * Returns true is the given waitq is a member of at least 1 set | |
4286 | */ | |
4287 | boolean_t waitq_in_set(struct waitq *waitq) | |
4288 | { | |
4289 | struct setid_link *link; | |
4290 | boolean_t inset = FALSE; | |
4291 | spl_t s; | |
4292 | ||
4293 | if (waitq_irq_safe(waitq)) | |
4294 | s = splsched(); | |
4295 | waitq_lock(waitq); | |
4296 | ||
4297 | if (!waitq->waitq_set_id) | |
4298 | goto out_unlock; | |
4299 | ||
4300 | link = lt_get_link(waitq->waitq_set_id); | |
4301 | if (link) { | |
4302 | /* if we get here, the waitq is in _at_least_one_ set */ | |
4303 | inset = TRUE; | |
4304 | lt_put_link(link); | |
4305 | } else { | |
4306 | /* we can just optimize this for next time */ | |
4307 | waitq->waitq_set_id = 0; | |
4308 | } | |
4309 | ||
4310 | out_unlock: | |
4311 | waitq_unlock(waitq); | |
4312 | if (waitq_irq_safe(waitq)) | |
4313 | splx(s); | |
4314 | return inset; | |
4315 | } | |
4316 | ||
4317 | ||
4318 | /** | |
4319 | * pre-allocate a waitq link structure from the link table | |
4320 | * | |
4321 | * Conditions: | |
4322 | * 'waitq' is not locked | |
4323 | * may (rarely) block if link table needs to grow | |
4324 | */ | |
4325 | uint64_t waitq_link_reserve(struct waitq *waitq) | |
4326 | { | |
4327 | struct setid_link *link; | |
4328 | uint64_t reserved_id = 0; | |
4329 | ||
4330 | assert(get_preemption_level() == 0 && waitq_wait_possible(current_thread())); | |
4331 | ||
4332 | /* | |
4333 | * We've asserted that the caller can block, so we enforce a | |
4334 | * minimum-free table element policy here. | |
4335 | */ | |
4336 | lt_ensure_free_space(); | |
4337 | ||
4338 | (void)waitq; | |
4339 | link = lt_alloc_link(WQT_RESERVED); | |
4340 | if (!link) | |
4341 | return 0; | |
4342 | ||
4343 | reserved_id = link->sl_set_id.id; | |
4344 | ||
4345 | return reserved_id; | |
4346 | } | |
4347 | ||
4348 | /** | |
4349 | * release a pre-allocated waitq link structure | |
4350 | */ | |
4351 | void waitq_link_release(uint64_t id) | |
4352 | { | |
4353 | struct setid_link *link; | |
4354 | ||
4355 | if (id == 0) | |
4356 | return; | |
4357 | ||
4358 | link = lt_get_reserved(id, SLT_LINK); | |
4359 | if (!link) | |
4360 | return; | |
4361 | ||
4362 | /* | |
4363 | * if we successfully got a link object, then we know | |
4364 | * it's not been marked valid, and can be released with | |
4365 | * a standard lt_put_link() which should free the element. | |
4366 | */ | |
4367 | lt_put_link(link); | |
4368 | #if CONFIG_WAITQ_STATS | |
4369 | g_linktable.nreserved_releases += 1; | |
4370 | #endif | |
4371 | } | |
4372 | ||
4373 | /** | |
4374 | * link 'waitq' to the set identified by 'setid' using the 'link' structure | |
4375 | * | |
4376 | * Conditions: | |
4377 | * 'waitq' is locked | |
4378 | * caller should have a reference to the 'link' object | |
4379 | */ | |
4380 | static kern_return_t waitq_link_internal(struct waitq *waitq, | |
4381 | uint64_t setid, struct setid_link *link) | |
4382 | { | |
4383 | struct setid_link *qlink; | |
4384 | kern_return_t kr; | |
4385 | ||
4386 | assert(waitq_held(waitq)); | |
4387 | ||
4388 | /* | |
4389 | * If the waitq_set_id field is empty, then this waitq is not | |
4390 | * a member of any other set. All we have to do is update the | |
4391 | * field. | |
4392 | */ | |
4393 | if (!waitq->waitq_set_id) { | |
4394 | waitq->waitq_set_id = setid; | |
4395 | return KERN_SUCCESS; | |
4396 | } | |
4397 | ||
4398 | qlink = lt_get_link(waitq->waitq_set_id); | |
4399 | if (!qlink) { | |
4400 | /* | |
4401 | * The set to which this wait queue belonged has been | |
4402 | * destroyed / invalidated. We can re-use the waitq field. | |
4403 | */ | |
4404 | waitq->waitq_set_id = setid; | |
4405 | return KERN_SUCCESS; | |
4406 | } | |
4407 | lt_put_link(qlink); | |
4408 | ||
4409 | /* | |
4410 | * Check to see if it's already a member of the set. | |
4411 | * | |
4412 | * TODO: check for cycles! | |
4413 | */ | |
4414 | kr = walk_setid_links(LINK_WALK_ONE_LEVEL, waitq, waitq->waitq_set_id, | |
4415 | SLT_ALL, (void *)&setid, waitq_inset_cb); | |
4416 | if (kr == WQ_ITERATE_FOUND) | |
4417 | return kr; | |
4418 | ||
4419 | /* | |
4420 | * This wait queue is a member of at least one set already, | |
4421 | * and _not_ a member of the given set. Use our previously | |
4422 | * allocated link object, and hook it up to the wait queue. | |
4423 | * Note that it's possible that one or more of the wait queue sets to | |
4424 | * which the wait queue belongs was invalidated before we allocated | |
4425 | * this link object. That's OK because the next time we use that | |
4426 | * object we'll just ignore it. | |
4427 | */ | |
4428 | link->sl_link.sl_left_setid = setid; | |
4429 | link->sl_link.sl_right_setid = waitq->waitq_set_id; | |
4430 | sl_set_valid(link); | |
4431 | ||
4432 | waitq->waitq_set_id = link->sl_set_id.id; | |
4433 | ||
4434 | return KERN_SUCCESS; | |
4435 | } | |
4436 | ||
4437 | /** | |
4438 | * link 'waitq' to 'wqset' | |
4439 | * | |
4440 | * Conditions: | |
4441 | * if 'lock_state' contains WAITQ_SHOULD_LOCK, 'waitq' must be unlocked. | |
4442 | * Otherwise, 'waitq' must be locked. | |
4443 | * | |
4444 | * may (rarely) block on link table allocation if the table has to grow, | |
4445 | * and no 'reserved_link' object is passed. | |
4446 | * | |
4447 | * Notes: | |
4448 | * The caller can guarantee that this function will never block by | |
4449 | * pre-allocating a link table object and passing its ID in 'reserved_link' | |
4450 | */ | |
4451 | kern_return_t waitq_link(struct waitq *waitq, struct waitq_set *wqset, | |
4452 | waitq_lock_state_t lock_state, uint64_t *reserved_link) | |
4453 | { | |
4454 | kern_return_t kr; | |
4455 | struct setid_link *link; | |
4456 | int should_lock = (lock_state == WAITQ_SHOULD_LOCK); | |
4457 | spl_t s; | |
4458 | ||
4459 | if (!waitq_valid(waitq)) | |
4460 | panic("Invalid waitq: %p", waitq); | |
4461 | ||
4462 | if (!waitqs_is_set(wqset)) | |
4463 | return KERN_INVALID_ARGUMENT; | |
4464 | ||
4465 | wqdbg_v("Link waitq %p to wqset 0x%llx", | |
4466 | (void *)VM_KERNEL_UNSLIDE_OR_PERM(waitq), wqset->wqset_id); | |
4467 | ||
4468 | if (waitq_irq_safe(waitq) && (!reserved_link || *reserved_link == 0)) { | |
4469 | /* | |
4470 | * wait queues that need IRQs disabled cannot block waiting | |
4471 | * for table growth to complete. Even though this is rare, | |
4472 | * we require all these waitqs to pass in a reserved link | |
4473 | * object to avoid the potential to block. | |
4474 | */ | |
4475 | panic("Global/IRQ-safe waitq %p cannot link to %p without" | |
4476 | "reserved object!", waitq, wqset); | |
4477 | } | |
4478 | ||
4479 | /* | |
4480 | * We _might_ need a new link object here, so we'll grab outside | |
4481 | * the lock because the alloc call _might_ block. | |
4482 | * | |
4483 | * If the caller reserved a link beforehand, then lt_get_link | |
4484 | * is guaranteed not to block because the caller holds an extra | |
4485 | * reference to the link which, in turn, hold a reference to the | |
4486 | * link table. | |
4487 | */ | |
4488 | if (reserved_link && *reserved_link != 0) { | |
4489 | link = lt_get_reserved(*reserved_link, SLT_LINK); | |
4490 | /* always consume the caller's reference */ | |
4491 | *reserved_link = 0; | |
4492 | } else { | |
4493 | link = lt_alloc_link(SLT_LINK); | |
4494 | } | |
4495 | if (!link) | |
4496 | return KERN_NO_SPACE; | |
4497 | ||
4498 | if (should_lock) { | |
4499 | if (waitq_irq_safe(waitq)) | |
4500 | s = splsched(); | |
4501 | waitq_lock(waitq); | |
4502 | } | |
4503 | ||
4504 | kr = waitq_link_internal(waitq, wqset->wqset_id, link); | |
4505 | ||
4506 | if (should_lock) { | |
4507 | waitq_unlock(waitq); | |
4508 | if (waitq_irq_safe(waitq)) | |
4509 | splx(s); | |
4510 | } | |
4511 | ||
4512 | lt_put_link(link); | |
4513 | ||
4514 | return kr; | |
4515 | } | |
4516 | ||
4517 | /** | |
4518 | * helper: unlink 'waitq' from waitq set identified by 'setid' | |
4519 | * this function also prunes invalid objects from the tree | |
4520 | * | |
4521 | * Conditions: | |
4522 | * MUST be called from walk_setid_links link table walk | |
4523 | * 'waitq' is locked | |
4524 | * | |
4525 | * Notes: | |
4526 | * This is a helper function which compresses the link table by culling | |
4527 | * unused or unnecessary links. See comments below for different | |
4528 | * scenarios. | |
4529 | */ | |
4530 | static inline int waitq_maybe_remove_link(struct waitq *waitq, | |
4531 | uint64_t setid, | |
4532 | struct setid_link *parent, | |
4533 | struct setid_link *left, | |
4534 | struct setid_link *right) | |
4535 | { | |
4536 | uint64_t *wq_setid = &waitq->waitq_set_id; | |
4537 | ||
4538 | /* | |
4539 | * There are two scenarios: | |
4540 | * | |
4541 | * Scenario 1: | |
4542 | * -------------------------------------------------------------------- | |
4543 | * waitq->waitq_set_id == parent | |
4544 | * | |
4545 | * parent(LINK) | |
4546 | * / \ | |
4547 | * / \ | |
4548 | * / \ | |
4549 | * L(LINK/WQS_l) R(LINK/WQS_r) | |
4550 | * | |
4551 | * In this scenario, we assert that the original waitq points to the | |
4552 | * parent link we were passed in. If WQS_l (or WQS_r) is the waitq | |
4553 | * set we're looking for, we can set the corresponding parent | |
4554 | * link id (left or right) to 0. To compress the tree, we can reset the | |
4555 | * waitq_set_id of the original waitq to point to the side of the | |
4556 | * parent that is still valid. We then discard the parent link object. | |
4557 | */ | |
4558 | if (*wq_setid == parent->sl_set_id.id) { | |
4559 | if (!left && !right) { | |
4560 | /* completely invalid children */ | |
4561 | lt_invalidate(parent); | |
4562 | wqdbg_v("S1, L+R"); | |
4563 | *wq_setid = 0; | |
4564 | return WQ_ITERATE_INVALID; | |
4565 | } else if (!left || left->sl_set_id.id == setid) { | |
4566 | /* | |
4567 | * left side matches we know it points either to the | |
4568 | * WQS we're unlinking, or to an invalid object: | |
4569 | * no need to invalidate it | |
4570 | */ | |
4571 | *wq_setid = right->sl_set_id.id; | |
4572 | lt_invalidate(parent); | |
4573 | wqdbg_v("S1, L"); | |
4574 | return left ? WQ_ITERATE_UNLINKED : WQ_ITERATE_INVALID; | |
4575 | } else if (!right || right->sl_set_id.id == setid) { | |
4576 | /* | |
4577 | * if right side matches we know it points either to the | |
4578 | * WQS we're unlinking, or to an invalid object: | |
4579 | * no need to invalidate it | |
4580 | */ | |
4581 | *wq_setid = left->sl_set_id.id; | |
4582 | lt_invalidate(parent); | |
4583 | wqdbg_v("S1, R"); | |
4584 | return right ? WQ_ITERATE_UNLINKED : WQ_ITERATE_INVALID; | |
4585 | } | |
4586 | } | |
4587 | ||
4588 | /* | |
4589 | * the tree walk starts at the top-of-tree and moves down, | |
4590 | * so these are safe asserts. | |
4591 | */ | |
4592 | assert(left || right); /* one of them has to be valid at this point */ | |
4593 | ||
4594 | /* | |
4595 | * Scenario 2: | |
4596 | * -------------------------------------------------------------------- | |
4597 | * waitq->waitq_set_id == ... (OR parent) | |
4598 | * | |
4599 | * ... | |
4600 | * | | |
4601 | * parent | |
4602 | * / \ | |
4603 | * / \ | |
4604 | * L(LINK) R(LINK) | |
4605 | * /\ /\ | |
4606 | * / \ / \ | |
4607 | * / \ Rl(*) Rr(*) | |
4608 | * Ll(WQS) Lr(WQS) | |
4609 | * | |
4610 | * In this scenario, a leaf node of either the left or right side | |
4611 | * could be the wait queue set we're looking to unlink. We also handle | |
4612 | * the case where one of these links is invalid. If a leaf node is | |
4613 | * invalid or it's the set we're looking for, we can safely remove the | |
4614 | * middle link (left or right) and point the parent link directly to | |
4615 | * the remaining leaf node. | |
4616 | */ | |
4617 | if (left && sl_type(left) == SLT_LINK) { | |
4618 | uint64_t Ll, Lr; | |
4619 | struct setid_link *linkLl, *linkLr; | |
4620 | assert(left->sl_set_id.id != setid); | |
4621 | Ll = left->sl_link.sl_left_setid; | |
4622 | Lr = left->sl_link.sl_right_setid; | |
4623 | linkLl = lt_get_link(Ll); | |
4624 | linkLr = lt_get_link(Lr); | |
4625 | if (!linkLl && !linkLr) { | |
4626 | /* | |
4627 | * The left object points to two invalid objects! | |
4628 | * We can invalidate the left w/o touching the parent. | |
4629 | */ | |
4630 | lt_invalidate(left); | |
4631 | wqdbg_v("S2, Ll+Lr"); | |
4632 | return WQ_ITERATE_INVALID; | |
4633 | } else if (!linkLl || Ll == setid) { | |
4634 | /* Ll is invalid and/or the wait queue set we're looking for */ | |
4635 | parent->sl_link.sl_left_setid = Lr; | |
4636 | lt_invalidate(left); | |
4637 | lt_put_link(linkLl); | |
4638 | lt_put_link(linkLr); | |
4639 | wqdbg_v("S2, Ll"); | |
4640 | return linkLl ? WQ_ITERATE_UNLINKED : WQ_ITERATE_INVALID; | |
4641 | } else if (!linkLr || Lr == setid) { | |
4642 | /* Lr is invalid and/or the wait queue set we're looking for */ | |
4643 | parent->sl_link.sl_left_setid = Ll; | |
4644 | lt_invalidate(left); | |
4645 | lt_put_link(linkLr); | |
4646 | lt_put_link(linkLl); | |
4647 | wqdbg_v("S2, Lr"); | |
4648 | return linkLr ? WQ_ITERATE_UNLINKED : WQ_ITERATE_INVALID; | |
4649 | } | |
4650 | lt_put_link(linkLl); | |
4651 | lt_put_link(linkLr); | |
4652 | } | |
4653 | ||
4654 | if (right && sl_type(right) == SLT_LINK) { | |
4655 | uint64_t Rl, Rr; | |
4656 | struct setid_link *linkRl, *linkRr; | |
4657 | assert(right->sl_set_id.id != setid); | |
4658 | Rl = right->sl_link.sl_left_setid; | |
4659 | Rr = right->sl_link.sl_right_setid; | |
4660 | linkRl = lt_get_link(Rl); | |
4661 | linkRr = lt_get_link(Rr); | |
4662 | if (!linkRl && !linkRr) { | |
4663 | /* | |
4664 | * The right object points to two invalid objects! | |
4665 | * We can invalidate the right w/o touching the parent. | |
4666 | */ | |
4667 | lt_invalidate(right); | |
4668 | wqdbg_v("S2, Rl+Rr"); | |
4669 | return WQ_ITERATE_INVALID; | |
4670 | } else if (!linkRl || Rl == setid) { | |
4671 | /* Rl is invalid and/or the wait queue set we're looking for */ | |
4672 | parent->sl_link.sl_right_setid = Rr; | |
4673 | lt_invalidate(right); | |
4674 | lt_put_link(linkRl); | |
4675 | lt_put_link(linkRr); | |
4676 | wqdbg_v("S2, Rl"); | |
4677 | return linkRl ? WQ_ITERATE_UNLINKED : WQ_ITERATE_INVALID; | |
4678 | } else if (!linkRr || Rr == setid) { | |
4679 | /* Rr is invalid and/or the wait queue set we're looking for */ | |
4680 | parent->sl_link.sl_right_setid = Rl; | |
4681 | lt_invalidate(right); | |
4682 | lt_put_link(linkRl); | |
4683 | lt_put_link(linkRr); | |
4684 | wqdbg_v("S2, Rr"); | |
4685 | return linkRr ? WQ_ITERATE_UNLINKED : WQ_ITERATE_INVALID; | |
4686 | } | |
4687 | lt_put_link(linkRl); | |
4688 | lt_put_link(linkRr); | |
4689 | } | |
4690 | ||
4691 | return WQ_ITERATE_CONTINUE; | |
4692 | } | |
4693 | ||
4694 | /** | |
4695 | * link table walk callback that unlinks 'waitq' from 'ctx->setid' | |
4696 | * | |
4697 | * Conditions: | |
4698 | * called from walk_setid_links | |
4699 | * 'waitq' is locked | |
4700 | * | |
4701 | * Notes: | |
4702 | * uses waitq_maybe_remove_link() to compress the linktable and | |
4703 | * perform the actual unlinking | |
4704 | */ | |
4705 | static int waitq_unlink_cb(struct waitq *waitq, void *ctx, | |
4706 | struct setid_link *link) | |
4707 | { | |
4708 | uint64_t setid = *((uint64_t *)ctx); | |
4709 | struct setid_link *right, *left; | |
4710 | int ret = 0; | |
4711 | ||
4712 | if (sl_type(link) != SLT_LINK) | |
4713 | return WQ_ITERATE_CONTINUE; | |
4714 | ||
4715 | do { | |
4716 | left = lt_get_link(link->sl_link.sl_left_setid); | |
4717 | right = lt_get_link(link->sl_link.sl_right_setid); | |
4718 | ||
4719 | ret = waitq_maybe_remove_link(waitq, setid, link, left, right); | |
4720 | ||
4721 | lt_put_link(left); | |
4722 | lt_put_link(right); | |
4723 | ||
4724 | if (!sl_is_valid(link)) | |
4725 | return WQ_ITERATE_INVALID; | |
4726 | /* A ret value of UNLINKED will break us out of table walk */ | |
4727 | } while (ret == WQ_ITERATE_INVALID); | |
4728 | ||
4729 | return ret; | |
4730 | } | |
4731 | ||
4732 | ||
4733 | /** | |
4734 | * undo/remove a prepost from 'ctx' (waitq) to 'wqset' | |
4735 | * | |
4736 | * Conditions: | |
4737 | * Called from wq_prepost_foreach_locked OR wq_prepost_iterate | |
4738 | * 'wqset' may be NULL | |
4739 | * (ctx)->unlink_wqset is locked | |
4740 | */ | |
4741 | static int waitq_unlink_prepost_cb(struct waitq_set __unused *wqset, void *ctx, | |
4742 | struct wq_prepost *wqp, struct waitq *waitq) | |
4743 | { | |
4744 | struct wq_unlink_ctx *ulctx = (struct wq_unlink_ctx *)ctx; | |
4745 | ||
4746 | if (waitq != ulctx->unlink_wq) | |
4747 | return WQ_ITERATE_CONTINUE; | |
4748 | ||
4749 | if (wqp_type(wqp) == WQP_WQ && | |
4750 | wqp->wqp_prepostid.id == ulctx->unlink_wqset->wqset_prepost_id) { | |
4751 | /* this is the only prepost on this wait queue set */ | |
4752 | wqdbg_v("unlink wqp (WQ) 0x%llx", wqp->wqp_prepostid.id); | |
4753 | ulctx->unlink_wqset->wqset_prepost_id = 0; | |
4754 | return WQ_ITERATE_BREAK; | |
4755 | } | |
4756 | ||
4757 | assert(wqp_type(wqp) == WQP_POST); | |
4758 | ||
4759 | /* | |
4760 | * The prepost object 'wqp' points to a waitq which should no longer | |
4761 | * be preposted to 'ulctx->unlink_wqset'. We can remove the prepost | |
4762 | * object from the list and break out of the iteration. Using the | |
4763 | * context object in this way allows this same callback function to be | |
4764 | * used from both wq_prepost_foreach_locked and wq_prepost_iterate. | |
4765 | */ | |
4766 | wq_prepost_remove(ulctx->unlink_wqset, wqp); | |
4767 | return WQ_ITERATE_BREAK; | |
4768 | } | |
4769 | ||
4770 | /** | |
4771 | * unlink 'waitq' from 'wqset' | |
4772 | * | |
4773 | * Conditions: | |
4774 | * 'waitq' is locked | |
4775 | * 'wqset' is _not_ locked | |
4776 | * may (rarely) spin in prepost clear and drop/re-acquire 'waitq' lock | |
4777 | * (see waitq_clear_prepost_locked) | |
4778 | */ | |
4779 | static kern_return_t waitq_unlink_locked(struct waitq *waitq, | |
4780 | struct waitq_set *wqset, | |
4781 | spl_t *s) | |
4782 | { | |
4783 | uint64_t setid; | |
4784 | kern_return_t kr; | |
4785 | ||
4786 | setid = wqset->wqset_id; | |
4787 | ||
4788 | if (waitq->waitq_set_id == 0) { | |
4789 | /* | |
4790 | * TODO: | |
4791 | * it doesn't belong to anyone, and it has a prepost object? | |
4792 | * This is an artifact of not cleaning up after kqueues when | |
4793 | * they prepost into select sets... | |
4794 | */ | |
4795 | if (waitq->waitq_prepost_id != 0) | |
4796 | (void)waitq_clear_prepost_locked(waitq, s); | |
4797 | return KERN_NOT_IN_SET; | |
4798 | } | |
4799 | ||
4800 | if (waitq->waitq_set_id == setid) { | |
4801 | waitq->waitq_set_id = 0; | |
4802 | /* | |
4803 | * This was the only set to which the waitq belonged: we can | |
4804 | * safely release the waitq's prepost object. It doesn't | |
4805 | * matter if this function drops and re-acquires the lock | |
4806 | * because we're not manipulating waitq state any more. | |
4807 | */ | |
4808 | (void)waitq_clear_prepost_locked(waitq, s); | |
4809 | return KERN_SUCCESS; | |
4810 | } | |
4811 | ||
4812 | /* | |
4813 | * The waitq was a member of more that 1 set, so we need to | |
4814 | * handle potentially compressing the link table, and | |
4815 | * adjusting the waitq->waitq_set_id value. | |
4816 | * | |
4817 | * Note: we can't free the waitq's associated prepost object (if any) | |
4818 | * because it may be in use by the one or more _other_ sets to | |
4819 | * which this queue belongs. | |
4820 | * | |
4821 | * Note: This function only handles a single level of the queue linkage. | |
4822 | * Removing a waitq from a set to which it does not directly | |
4823 | * belong is undefined. For example, if a waitq belonged to set | |
4824 | * A, and set A belonged to set B. You can't remove the waitq | |
4825 | * from set B. | |
4826 | */ | |
4827 | kr = walk_setid_links(LINK_WALK_ONE_LEVEL, waitq, waitq->waitq_set_id, | |
4828 | SLT_LINK, (void *)&setid, waitq_unlink_cb); | |
4829 | ||
4830 | if (kr == WQ_ITERATE_UNLINKED) { | |
4831 | struct wq_unlink_ctx ulctx; | |
4832 | int do_spl = 0; | |
4833 | ||
4834 | kr = KERN_SUCCESS; /* found it and dis-associated it */ | |
4835 | ||
4836 | if (!waitq_irq_safe(waitq) && waitq_irq_safe(&wqset->wqset_q)) { | |
4837 | *s = splsched(); | |
4838 | do_spl = 1; | |
4839 | } | |
4840 | waitq_set_lock(wqset); | |
4841 | /* | |
4842 | * clear out any prepost from waitq into wqset | |
4843 | * TODO: this could be more efficient than a linear search of | |
4844 | * the waitq set's prepost list. | |
4845 | */ | |
4846 | ulctx.unlink_wq = waitq; | |
4847 | ulctx.unlink_wqset = wqset; | |
4848 | (void)wq_prepost_iterate(wqset->wqset_prepost_id, (void *)&ulctx, | |
4849 | waitq_unlink_prepost_cb); | |
4850 | waitq_set_unlock(wqset); | |
4851 | if (do_spl) | |
4852 | splx(*s); | |
4853 | } else { | |
4854 | kr = KERN_NOT_IN_SET; /* waitq is _not_ associated with wqset */ | |
4855 | } | |
4856 | ||
4857 | return kr; | |
4858 | } | |
4859 | ||
4860 | /** | |
4861 | * unlink 'waitq' from 'wqset' | |
4862 | * | |
4863 | * Conditions: | |
4864 | * neither 'waitq' nor 'wqset' is locked | |
4865 | * may disable and re-enable interrupts | |
4866 | * may (rarely) spin in prepost clear | |
4867 | * (see waitq_clear_prepost_locked) | |
4868 | */ | |
4869 | kern_return_t waitq_unlink(struct waitq *waitq, struct waitq_set *wqset) | |
4870 | { | |
4871 | kern_return_t kr = KERN_SUCCESS; | |
4872 | spl_t s; | |
4873 | ||
4874 | assert(waitqs_is_set(wqset)); | |
4875 | ||
4876 | /* | |
4877 | * we allow the waitq to be invalid because the caller may be trying | |
4878 | * to clear out old/dirty state | |
4879 | */ | |
4880 | if (!waitq_valid(waitq)) | |
4881 | return KERN_INVALID_ARGUMENT; | |
4882 | ||
4883 | wqdbg_v("unlink waitq %p from set 0x%llx", | |
4884 | (void *)VM_KERNEL_UNSLIDE_OR_PERM(waitq), wqset->wqset_id); | |
4885 | ||
4886 | if (waitq_irq_safe(waitq)) | |
4887 | s = splsched(); | |
4888 | waitq_lock(waitq); | |
4889 | ||
4890 | kr = waitq_unlink_locked(waitq, wqset, &s); | |
4891 | ||
4892 | waitq_unlock(waitq); | |
4893 | if (waitq_irq_safe(waitq)) | |
4894 | splx(s); | |
4895 | ||
4896 | return kr; | |
4897 | } | |
4898 | ||
4899 | /** | |
4900 | * unlink a waitq from a waitq set, but reference the waitq by its prepost ID | |
4901 | * | |
4902 | * Conditions: | |
4903 | * 'wqset' is unlocked | |
4904 | * wqp_id may be valid or invalid | |
4905 | */ | |
4906 | void waitq_unlink_by_prepost_id(uint64_t wqp_id, struct waitq_set *wqset) | |
4907 | { | |
4908 | struct wq_prepost *wqp; | |
4909 | ||
4910 | disable_preemption(); | |
4911 | wqp = wq_prepost_get(wqp_id); | |
4912 | if (wqp) { | |
4913 | struct waitq *wq; | |
4914 | spl_t s; | |
4915 | ||
4916 | wq = wqp->wqp_wq.wqp_wq_ptr; | |
4917 | ||
4918 | /* | |
4919 | * lock the waitq, then release our prepost ID reference, then | |
4920 | * unlink the waitq from the wqset: this ensures that we don't | |
4921 | * hold a prepost ID reference during the unlink, but we also | |
4922 | * complete the unlink operation atomically to avoid a race | |
4923 | * with waitq_unlink[_all]. | |
4924 | */ | |
4925 | if (waitq_irq_safe(wq)) | |
4926 | s = splsched(); | |
4927 | waitq_lock(wq); | |
4928 | wq_prepost_put(wqp); | |
4929 | ||
4930 | if (!waitq_valid(wq)) { | |
4931 | /* someone already tore down this waitq! */ | |
4932 | waitq_unlock(wq); | |
4933 | if (waitq_irq_safe(wq)) | |
4934 | splx(s); | |
4935 | enable_preemption(); | |
4936 | return; | |
4937 | } | |
4938 | ||
4939 | /* this _may_ drop the wq lock, but that's OK */ | |
4940 | waitq_unlink_locked(wq, wqset, &s); | |
4941 | ||
4942 | waitq_unlock(wq); | |
4943 | if (waitq_irq_safe(wq)) | |
4944 | splx(s); | |
4945 | } | |
4946 | enable_preemption(); | |
4947 | return; | |
4948 | } | |
4949 | ||
4950 | ||
4951 | /** | |
4952 | * unlink 'waitq' from all sets to which it belongs | |
4953 | * | |
4954 | * Conditions: | |
4955 | * 'waitq' is locked | |
4956 | * | |
4957 | * Notes: | |
4958 | * may drop and re-acquire the waitq lock | |
4959 | * may (rarely) spin (see waitq_clear_prepost_locked) | |
4960 | */ | |
4961 | kern_return_t waitq_unlink_all_locked(struct waitq *waitq, uint64_t *old_set_id, | |
4962 | spl_t *s, int *dropped_lock) | |
4963 | { | |
4964 | wqdbg_v("unlink waitq %p from all sets", | |
4965 | (void *)VM_KERNEL_UNSLIDE_OR_PERM(waitq)); | |
4966 | ||
4967 | *old_set_id = 0; | |
4968 | ||
4969 | /* it's not a member of any sets */ | |
4970 | if (waitq->waitq_set_id == 0) | |
4971 | return KERN_SUCCESS; | |
4972 | ||
4973 | *old_set_id = waitq->waitq_set_id; | |
4974 | waitq->waitq_set_id = 0; | |
4975 | ||
4976 | /* | |
4977 | * invalidate the prepost entry for this waitq. | |
4978 | * This may drop and re-acquire the waitq lock, but that's OK because | |
4979 | * if it was added to another set and preposted to that set in the | |
4980 | * time we drop the lock, the state will remain consistent. | |
4981 | */ | |
4982 | int dropped = waitq_clear_prepost_locked(waitq, s); | |
4983 | if (dropped_lock) | |
4984 | *dropped_lock = dropped; | |
4985 | ||
4986 | return KERN_SUCCESS; | |
4987 | } | |
4988 | ||
4989 | /** | |
4990 | * unlink 'waitq' from all sets to which it belongs | |
4991 | * | |
4992 | * Conditions: | |
4993 | * 'waitq' is not locked | |
4994 | * may disable and re-enable interrupts | |
4995 | * may (rarely) spin | |
4996 | * (see waitq_unlink_all_locked, waitq_clear_prepost_locked) | |
4997 | */ | |
4998 | kern_return_t waitq_unlink_all(struct waitq *waitq) | |
4999 | { | |
5000 | kern_return_t kr = KERN_SUCCESS; | |
5001 | uint64_t setid = 0; | |
5002 | spl_t s; | |
5003 | ||
5004 | if (!waitq_valid(waitq)) | |
5005 | panic("Invalid waitq: %p", waitq); | |
5006 | ||
5007 | if (waitq_irq_safe(waitq)) | |
5008 | s = splsched(); | |
5009 | waitq_lock(waitq); | |
5010 | if (waitq_valid(waitq)) | |
5011 | kr = waitq_unlink_all_locked(waitq, &setid, &s, NULL); | |
5012 | waitq_unlock(waitq); | |
5013 | if (waitq_irq_safe(waitq)) | |
5014 | splx(s); | |
5015 | ||
5016 | if (setid) { | |
5017 | /* | |
5018 | * Walk the link table and invalidate each LINK object that | |
5019 | * used to connect this waitq to one or more sets: this works | |
5020 | * because SLT_LINK objects are private to each wait queue | |
5021 | */ | |
5022 | (void)walk_setid_links(LINK_WALK_ONE_LEVEL, waitq, setid, | |
5023 | SLT_LINK, NULL, waitq_unlink_all_cb); | |
5024 | } | |
5025 | ||
5026 | return kr; | |
5027 | } | |
5028 | ||
5029 | ||
5030 | /** | |
5031 | * unlink all waitqs from 'wqset' | |
5032 | * | |
5033 | * Conditions: | |
5034 | * 'wqset' is not locked | |
5035 | * may (rarely) spin/block (see waitq_clear_prepost_locked) | |
5036 | */ | |
5037 | kern_return_t waitq_set_unlink_all(struct waitq_set *wqset) | |
5038 | { | |
5039 | struct setid_link *link; | |
5040 | uint64_t prepost_id, set_links_id = 0; | |
5041 | spl_t spl; | |
5042 | ||
5043 | assert(waitqs_is_set(wqset)); | |
5044 | ||
5045 | wqdbg_v("unlink all queues from set 0x%llx", wqset->wqset_id); | |
5046 | ||
5047 | /* | |
5048 | * This operation does not require interaction with any of the set's | |
5049 | * constituent wait queues. All we have to do is invalidate the SetID | |
5050 | */ | |
5051 | if (waitq_irq_safe(&wqset->wqset_q)) | |
5052 | spl = splsched(); | |
5053 | waitq_set_lock(wqset); | |
5054 | ||
5055 | /* invalidate and re-alloc the link object first */ | |
5056 | link = lt_get_link(wqset->wqset_id); | |
5057 | ||
5058 | /* we may have raced with a waitq_set_deinit: handle this */ | |
5059 | if (!link) { | |
5060 | waitq_set_unlock(wqset); | |
5061 | return KERN_SUCCESS; | |
5062 | } | |
5063 | ||
5064 | lt_invalidate(link); | |
5065 | ||
5066 | /* re-alloc the object to get a new generation ID */ | |
5067 | lt_realloc_link(link, SLT_WQS); | |
5068 | link->sl_wqs.sl_set = wqset; | |
5069 | ||
5070 | wqset->wqset_id = link->sl_set_id.id; | |
5071 | sl_set_valid(link); | |
5072 | lt_put_link(link); | |
5073 | ||
5074 | /* clear any preposts attached to this set */ | |
5075 | prepost_id = wqset->wqset_prepost_id; | |
5076 | wqset->wqset_prepost_id = 0; | |
5077 | ||
5078 | /* | |
5079 | * clear set linkage and prepost object associated with this set: | |
5080 | * waitq sets may prepost to other sets if, for example, they are | |
5081 | * associated with a kqueue which is in a select set. | |
5082 | * | |
5083 | * This may drop and re-acquire the set lock, but that's OK because | |
5084 | * the resulting state will remain consistent. | |
5085 | */ | |
5086 | waitq_unlink_all_locked(&wqset->wqset_q, &set_links_id, &spl, NULL); | |
5087 | ||
5088 | waitq_set_unlock(wqset); | |
5089 | if (waitq_irq_safe(&wqset->wqset_q)) | |
5090 | splx(spl); | |
5091 | ||
5092 | /* | |
5093 | * release all the set link objects | |
5094 | * (links to other sets to which this set was previously added) | |
5095 | */ | |
5096 | if (set_links_id) | |
5097 | (void)walk_setid_links(LINK_WALK_ONE_LEVEL, &wqset->wqset_q, | |
5098 | set_links_id, SLT_LINK, NULL, | |
5099 | waitq_unlink_all_cb); | |
5100 | ||
5101 | /* drop / unlink all the prepost table objects */ | |
5102 | if (prepost_id) | |
5103 | (void)wq_prepost_iterate(prepost_id, NULL, | |
5104 | wqset_clear_prepost_chain_cb); | |
5105 | ||
5106 | return KERN_SUCCESS; | |
5107 | } | |
5108 | ||
5109 | ||
5110 | static int waitq_prepost_reserve_cb(struct waitq *waitq, void *ctx, | |
5111 | struct setid_link *link) | |
5112 | { | |
5113 | uint32_t *num = (uint32_t *)ctx; | |
5114 | (void)waitq; | |
5115 | ||
5116 | /* | |
5117 | * In the worst case, we'll have to allocate 2 prepost objects | |
5118 | * per waitq set (if the set was already preposted by another | |
5119 | * waitq). | |
5120 | */ | |
5121 | if (sl_type(link) == SLT_WQS) { | |
5122 | /* | |
5123 | * check to see if the associated waitq actually supports | |
5124 | * preposting | |
5125 | */ | |
5126 | if (waitq_set_can_prepost(link->sl_wqs.sl_set)) | |
5127 | *num += 2; | |
5128 | } | |
5129 | return WQ_ITERATE_CONTINUE; | |
5130 | } | |
5131 | ||
5132 | static int waitq_alloc_prepost_reservation(int nalloc, struct waitq *waitq, | |
5133 | spl_t *s, int *did_unlock, | |
5134 | struct wq_prepost **wqp) | |
5135 | { | |
5136 | struct wq_prepost *tmp; | |
5137 | struct wqp_cache *cache; | |
5138 | ||
5139 | *did_unlock = 0; | |
5140 | ||
5141 | /* | |
5142 | * Before we unlock the waitq, check the per-processor prepost object | |
5143 | * cache to see if there's enough there for us. If so, do the | |
5144 | * allocation, keep the lock and save an entire iteration over the set | |
5145 | * linkage! | |
5146 | */ | |
5147 | if (waitq) { | |
5148 | disable_preemption(); | |
5149 | cache = &PROCESSOR_DATA(current_processor(), wqp_cache); | |
5150 | if (nalloc <= (int)cache->avail) | |
5151 | goto do_alloc; | |
5152 | enable_preemption(); | |
5153 | ||
5154 | /* unlock the waitq to perform the allocation */ | |
5155 | *did_unlock = 1; | |
5156 | waitq_unlock(waitq); | |
5157 | if (waitq_irq_safe(waitq)) | |
5158 | splx(*s); | |
5159 | } | |
5160 | ||
5161 | do_alloc: | |
5162 | tmp = wq_prepost_alloc(WQT_RESERVED, nalloc); | |
5163 | if (!tmp) | |
5164 | panic("Couldn't reserve %d preposts for waitq @%p (wqp@%p)", | |
5165 | nalloc, waitq, *wqp); | |
5166 | if (*wqp) { | |
5167 | /* link the two lists */ | |
5168 | int __assert_only rc; | |
5169 | rc = wq_prepost_rlink(tmp, *wqp); | |
5170 | assert(rc == nalloc); | |
5171 | } | |
5172 | *wqp = tmp; | |
5173 | ||
5174 | /* | |
5175 | * If the caller can block, then enforce a minimum-free table element | |
5176 | * policy here. This helps ensure that we will have enough prepost | |
5177 | * objects for callers such as selwakeup() that can be called with | |
5178 | * spin locks held. | |
5179 | */ | |
5180 | if (get_preemption_level() == 0) | |
5181 | wq_prepost_ensure_free_space(); | |
5182 | ||
5183 | if (waitq) { | |
5184 | if (*did_unlock == 0) { | |
5185 | /* decrement the preemption count if alloc from cache */ | |
5186 | enable_preemption(); | |
5187 | } else { | |
5188 | /* otherwise: re-lock the waitq */ | |
5189 | if (waitq_irq_safe(waitq)) | |
5190 | *s = splsched(); | |
5191 | waitq_lock(waitq); | |
5192 | } | |
5193 | } | |
5194 | ||
5195 | return nalloc; | |
5196 | } | |
5197 | ||
5198 | static int waitq_count_prepost_reservation(struct waitq *waitq, int extra, int keep_locked) | |
5199 | { | |
5200 | int npreposts = 0; | |
5201 | ||
5202 | /* | |
5203 | * If the waitq is not currently part of a set, and we're not asked to | |
5204 | * keep the waitq locked then we'll want to have 3 in reserve | |
5205 | * just-in-case it becomes part of a set while we unlock and reserve. | |
5206 | * We may need up to 1 object for the waitq, and 2 for the set. | |
5207 | */ | |
5208 | if (waitq->waitq_set_id == 0) { | |
5209 | npreposts = 3; | |
5210 | } else { | |
5211 | /* this queue has never been preposted before */ | |
5212 | if (waitq->waitq_prepost_id == 0) | |
5213 | npreposts = 3; | |
5214 | ||
5215 | /* | |
5216 | * Walk the set of table linkages associated with this waitq | |
5217 | * and count the worst-case number of prepost objects that | |
5218 | * may be needed during a wakeup_all. We can walk this without | |
5219 | * locking each set along the way because the table-based IDs | |
5220 | * disconnect us from the set pointers themselves, and the | |
5221 | * table walking is careful to read the setid values only once. | |
5222 | * Locking each set up the chain also doesn't guarantee that | |
5223 | * their membership won't change between the time we unlock | |
5224 | * that set and when we actually go to prepost, so our | |
5225 | * situation is no worse than before and we've alleviated lock | |
5226 | * contention on any sets to which this waitq belongs. | |
5227 | */ | |
5228 | (void)walk_setid_links(LINK_WALK_FULL_DAG_UNLOCKED, | |
5229 | waitq, waitq->waitq_set_id, | |
5230 | SLT_WQS, (void *)&npreposts, | |
5231 | waitq_prepost_reserve_cb); | |
5232 | } | |
5233 | ||
5234 | if (extra > 0) | |
5235 | npreposts += extra; | |
5236 | ||
5237 | if (npreposts == 0 && !keep_locked) { | |
5238 | /* | |
5239 | * If we get here, we were asked to reserve some prepost | |
5240 | * objects for a waitq that's previously preposted, and is not | |
5241 | * currently a member of any sets. We have also been | |
5242 | * instructed to unlock the waitq when we're done. In this | |
5243 | * case, we pre-allocated enough reserved objects to handle | |
5244 | * the case where the waitq gets added to a single set when | |
5245 | * the lock is released. | |
5246 | */ | |
5247 | npreposts = 3; | |
5248 | } | |
5249 | ||
5250 | return npreposts; | |
5251 | } | |
5252 | ||
5253 | ||
5254 | /** | |
5255 | * pre-allocate prepost objects for 'waitq' | |
5256 | * | |
5257 | * Conditions: | |
5258 | * 'waitq' is not locked | |
5259 | * | |
5260 | * Returns: | |
5261 | * panic on error | |
5262 | * | |
5263 | * 0 on success, '*reserved' is set to the head of a singly-linked | |
5264 | * list of pre-allocated prepost objects. | |
5265 | * | |
5266 | * Notes: | |
5267 | * If 'lock_state' is WAITQ_KEEP_LOCKED, this function performs the pre-allocation | |
5268 | * atomically and returns 'waitq' locked. If the waitq requires | |
5269 | * interrupts to be disabled, then the output parameter 's' is set to the | |
5270 | * previous interrupt state (from splsched), and the caller is | |
5271 | * responsible to call splx(). | |
5272 | * | |
5273 | * This function attempts to pre-allocate precisely enough prepost | |
5274 | * objects based on the current set membership of 'waitq'. If the | |
5275 | * operation is performed atomically, then the caller | |
5276 | * is guaranteed to have enough pre-allocated prepost object to avoid | |
5277 | * any (rare) blocking in the wakeup path. | |
5278 | */ | |
5279 | uint64_t waitq_prepost_reserve(struct waitq *waitq, int extra, | |
5280 | waitq_lock_state_t lock_state, spl_t *s) | |
5281 | { | |
5282 | uint64_t reserved = 0; | |
5283 | uint64_t prev_setid = 0, prev_prepostid = 0; | |
5284 | struct wq_prepost *wqp = NULL; | |
5285 | int nalloc = 0, npreposts = 0; | |
5286 | int keep_locked = (lock_state == WAITQ_KEEP_LOCKED); | |
5287 | int unlocked = 0; | |
5288 | ||
5289 | if (s) | |
5290 | *s = 0; | |
5291 | ||
5292 | wqdbg_v("Attempting to reserve prepost linkages for waitq %p (extra:%d)", | |
5293 | (void *)VM_KERNEL_UNSLIDE_OR_PERM(waitq), extra); | |
5294 | ||
5295 | if (waitq == NULL && extra > 0) { | |
5296 | /* | |
5297 | * Simple prepost object allocation: | |
5298 | * we'll add 2 more because the waitq might need an object, | |
5299 | * and the set itself may need a new POST object in addition | |
5300 | * to the number of preposts requested by the caller | |
5301 | */ | |
5302 | nalloc = waitq_alloc_prepost_reservation(extra + 2, NULL, NULL, | |
5303 | &unlocked, &wqp); | |
5304 | assert(nalloc == extra + 2); | |
5305 | return wqp->wqp_prepostid.id; | |
5306 | } | |
5307 | ||
5308 | assert(lock_state == WAITQ_KEEP_LOCKED || lock_state == WAITQ_UNLOCK); | |
5309 | ||
5310 | if (waitq_irq_safe(waitq)) | |
5311 | *s = splsched(); | |
5312 | waitq_lock(waitq); | |
5313 | ||
5314 | /* global queues are never part of any sets */ | |
5315 | if (waitq_is_global(waitq)) { | |
5316 | if (keep_locked) | |
5317 | goto out; | |
5318 | goto out_unlock; | |
5319 | } | |
5320 | ||
5321 | /* remember the set ID that we started with */ | |
5322 | prev_setid = waitq->waitq_set_id; | |
5323 | prev_prepostid = waitq->waitq_prepost_id; | |
5324 | ||
5325 | /* | |
5326 | * If the waitq is not part of a set, and we're asked to | |
5327 | * keep the set locked, then we don't have to reserve | |
5328 | * anything! | |
5329 | */ | |
5330 | if (prev_setid == 0 && keep_locked) | |
5331 | goto out; | |
5332 | ||
5333 | npreposts = waitq_count_prepost_reservation(waitq, extra, keep_locked); | |
5334 | ||
5335 | /* nothing for us to do! */ | |
5336 | if (npreposts == 0) { | |
5337 | if (keep_locked) | |
5338 | goto out; | |
5339 | goto out_unlock; | |
5340 | } | |
5341 | ||
5342 | try_alloc: | |
5343 | /* this _may_ unlock and relock the waitq! */ | |
5344 | nalloc = waitq_alloc_prepost_reservation(npreposts, waitq, s, | |
5345 | &unlocked, &wqp); | |
5346 | ||
5347 | if (!unlocked) { | |
5348 | /* allocation held the waitq lock: we'd done! */ | |
5349 | if (keep_locked) | |
5350 | goto out; | |
5351 | goto out_unlock; | |
5352 | } | |
5353 | ||
5354 | /* | |
5355 | * Before we return, if the allocation had to unlock the waitq, we | |
5356 | * must check one more time to see if we have enough. If not, we'll | |
5357 | * try to allocate the difference. If the caller requests it, we'll | |
5358 | * also leave the waitq locked so that the use of the pre-allocated | |
5359 | * prepost objects can be guaranteed to be enough if a wakeup_all is | |
5360 | * performed before unlocking the waitq. | |
5361 | */ | |
5362 | ||
5363 | /* | |
5364 | * If the waitq is no longer associated with a set, or if the waitq's | |
5365 | * set/prepostid has not changed since we first walked its linkage, | |
5366 | * we're done. | |
5367 | */ | |
5368 | if ((waitq->waitq_set_id == 0) || | |
5369 | (waitq->waitq_set_id == prev_setid && | |
5370 | waitq->waitq_prepost_id == prev_prepostid)) { | |
5371 | if (keep_locked) | |
5372 | goto out; | |
5373 | goto out_unlock; | |
5374 | } | |
5375 | ||
5376 | npreposts = waitq_count_prepost_reservation(waitq, extra, keep_locked); | |
5377 | ||
5378 | if (npreposts > nalloc) { | |
5379 | prev_setid = waitq->waitq_set_id; | |
5380 | prev_prepostid = waitq->waitq_prepost_id; | |
5381 | npreposts = npreposts - nalloc; /* only allocate the diff */ | |
5382 | goto try_alloc; | |
5383 | } | |
5384 | ||
5385 | if (keep_locked) | |
5386 | goto out; | |
5387 | ||
5388 | out_unlock: | |
5389 | waitq_unlock(waitq); | |
5390 | if (waitq_irq_safe(waitq)) | |
5391 | splx(*s); | |
5392 | out: | |
5393 | if (wqp) | |
5394 | reserved = wqp->wqp_prepostid.id; | |
5395 | ||
5396 | return reserved; | |
5397 | } | |
5398 | ||
5399 | /** | |
5400 | * release a linked list of prepost objects allocated via _prepost_reserve | |
5401 | * | |
5402 | * Conditions: | |
5403 | * may (rarely) spin waiting for prepost table growth memcpy | |
5404 | */ | |
5405 | void waitq_prepost_release_reserve(uint64_t id) | |
5406 | { | |
5407 | struct wq_prepost *wqp; | |
5408 | ||
5409 | wqdbg_v("releasing reserved preposts starting at: 0x%llx", id); | |
5410 | ||
5411 | wqp = wq_prepost_rfirst(id); | |
5412 | if (!wqp) | |
5413 | return; | |
5414 | ||
5415 | wq_prepost_release_rlist(wqp); | |
5416 | } | |
5417 | ||
5418 | ||
5419 | /** | |
5420 | * clear all preposts from 'wqset' | |
5421 | * | |
5422 | * Conditions: | |
5423 | * 'wqset' is not locked | |
5424 | */ | |
5425 | void waitq_set_clear_preposts(struct waitq_set *wqset) | |
5426 | { | |
5427 | uint64_t prepost_id; | |
5428 | spl_t spl; | |
5429 | ||
5430 | assert(waitqs_is_set(wqset)); | |
5431 | ||
5432 | wqdbg_v("Clearing all preposted queues on waitq_set: 0x%llx", | |
5433 | wqset->wqset_id); | |
5434 | ||
5435 | if (waitq_irq_safe(&wqset->wqset_q)) | |
5436 | spl = splsched(); | |
5437 | waitq_set_lock(wqset); | |
5438 | prepost_id = wqset->wqset_prepost_id; | |
5439 | wqset->wqset_prepost_id = 0; | |
5440 | waitq_set_unlock(wqset); | |
5441 | if (waitq_irq_safe(&wqset->wqset_q)) | |
5442 | splx(spl); | |
5443 | ||
5444 | /* drop / unlink all the prepost table objects */ | |
5445 | if (prepost_id) | |
5446 | (void)wq_prepost_iterate(prepost_id, NULL, | |
5447 | wqset_clear_prepost_chain_cb); | |
5448 | } | |
5449 | ||
5450 | ||
5451 | /* ---------------------------------------------------------------------- | |
5452 | * | |
5453 | * Iteration: waitq -> sets / waitq_set -> preposts | |
5454 | * | |
5455 | * ---------------------------------------------------------------------- */ | |
5456 | ||
5457 | struct wq_it_ctx { | |
5458 | void *input; | |
5459 | void *ctx; | |
5460 | waitq_iterator_t it; | |
5461 | ||
5462 | spl_t *spl; | |
5463 | }; | |
5464 | ||
5465 | static int waitq_iterate_sets_cb(struct waitq *waitq, void *ctx, | |
5466 | struct setid_link *link) | |
5467 | { | |
5468 | struct wq_it_ctx *wctx = (struct wq_it_ctx *)(ctx); | |
5469 | struct waitq_set *wqset; | |
5470 | int ret; | |
5471 | spl_t spl; | |
5472 | ||
5473 | (void)waitq; | |
5474 | assert(sl_type(link) == SLT_WQS); | |
5475 | ||
5476 | /* | |
5477 | * the waitq is locked, so we can just take the set lock | |
5478 | * and call the iterator function | |
5479 | */ | |
5480 | wqset = link->sl_wqs.sl_set; | |
5481 | assert(wqset != NULL); | |
5482 | ||
5483 | if (!waitq_irq_safe(waitq) && waitq_irq_safe(&wqset->wqset_q)) | |
5484 | spl = splsched(); | |
5485 | waitq_set_lock(wqset); | |
5486 | ||
5487 | ret = wctx->it(wctx->ctx, (struct waitq *)wctx->input, wqset); | |
5488 | ||
5489 | waitq_set_unlock(wqset); | |
5490 | if (!waitq_irq_safe(waitq) && waitq_irq_safe(&wqset->wqset_q)) | |
5491 | splx(spl); | |
5492 | ||
5493 | return ret; | |
5494 | } | |
5495 | ||
5496 | /** | |
5497 | * call external iterator function for each prepost object in wqset | |
5498 | * | |
5499 | * Conditions: | |
5500 | * Called from wq_prepost_foreach_locked | |
5501 | * (wqset locked, waitq _not_ locked) | |
5502 | */ | |
5503 | static int wqset_iterate_prepost_cb(struct waitq_set *wqset, void *ctx, | |
5504 | struct wq_prepost *wqp, struct waitq *waitq) | |
5505 | { | |
5506 | struct wq_it_ctx *wctx = (struct wq_it_ctx *)(ctx); | |
5507 | uint64_t wqp_id; | |
5508 | int ret; | |
5509 | spl_t s; | |
5510 | ||
5511 | (void)wqp; | |
5512 | ||
5513 | /* | |
5514 | * This is a bit tricky. The 'wqset' is locked, but the 'waitq' is not. | |
5515 | * Taking the 'waitq' lock is a lock order violation, so we need to be | |
5516 | * careful. We also must realize that we may have taken a reference to | |
5517 | * the 'wqp' just as the associated waitq was being torn down (or | |
5518 | * clearing all its preposts) - see waitq_clear_prepost_locked(). If | |
5519 | * the 'wqp' is valid and we can get the waitq lock, then we are good | |
5520 | * to go. If not, we need to back off, check that the 'wqp' hasn't | |
5521 | * been invalidated, and try to re-take the locks. | |
5522 | */ | |
5523 | if (waitq_irq_safe(waitq)) | |
5524 | s = splsched(); | |
5525 | if (waitq_lock_try(waitq)) | |
5526 | goto call_iterator; | |
5527 | ||
5528 | if (waitq_irq_safe(waitq)) | |
5529 | splx(s); | |
5530 | ||
5531 | if (!wqp_is_valid(wqp)) | |
5532 | return WQ_ITERATE_RESTART; | |
5533 | ||
5534 | /* We are passed a prepost object with a reference on it. If neither | |
5535 | * the waitq set nor the waitq require interrupts disabled, then we | |
5536 | * may block on the delay(1) call below. We can't hold a prepost | |
5537 | * object reference while blocking, so we have to give that up as well | |
5538 | * and re-acquire it when we come back. | |
5539 | */ | |
5540 | wqp_id = wqp->wqp_prepostid.id; | |
5541 | wq_prepost_put(wqp); | |
5542 | waitq_set_unlock(wqset); | |
5543 | wqdbg_v("dropped set:%p lock waiting for wqp:%p (0x%llx -> wq:%p)", | |
5544 | wqset, wqp, wqp->wqp_prepostid.id, waitq); | |
5545 | delay(1); | |
5546 | waitq_set_lock(wqset); | |
5547 | wqp = wq_prepost_get(wqp_id); | |
5548 | if (!wqp) | |
5549 | /* someone cleared preposts while we slept! */ | |
5550 | return WQ_ITERATE_DROPPED; | |
5551 | ||
5552 | /* | |
5553 | * TODO: | |
5554 | * This differs slightly from the logic in ipc_mqueue.c: | |
5555 | * ipc_mqueue_receive_on_thread(). There, if the waitq lock | |
5556 | * can't be obtained, the prepost link is placed on the back of | |
5557 | * the chain, and the iteration starts from the beginning. Here, | |
5558 | * we just restart from the beginning. | |
5559 | */ | |
5560 | return WQ_ITERATE_RESTART; | |
5561 | ||
5562 | call_iterator: | |
5563 | if (!wqp_is_valid(wqp)) { | |
5564 | ret = WQ_ITERATE_RESTART; | |
5565 | goto out_unlock; | |
5566 | } | |
5567 | ||
5568 | /* call the external callback */ | |
5569 | ret = wctx->it(wctx->ctx, waitq, wqset); | |
5570 | ||
5571 | if (ret == WQ_ITERATE_BREAK_KEEP_LOCKED) { | |
5572 | ret = WQ_ITERATE_BREAK; | |
5573 | if (wctx->spl) | |
5574 | *(wctx->spl) = s; | |
5575 | goto out; | |
5576 | } | |
5577 | ||
5578 | out_unlock: | |
5579 | waitq_unlock(waitq); | |
5580 | if (waitq_irq_safe(waitq)) | |
5581 | splx(s); | |
5582 | ||
5583 | out: | |
5584 | return ret; | |
5585 | } | |
5586 | ||
5587 | /** | |
5588 | * iterator over all sets to which the given waitq has been linked | |
5589 | * | |
5590 | * Conditions: | |
5591 | * 'waitq' is locked | |
5592 | */ | |
5593 | int waitq_iterate_sets(struct waitq *waitq, void *ctx, waitq_iterator_t it) | |
5594 | { | |
5595 | int ret; | |
5596 | struct wq_it_ctx wctx = { | |
5597 | .input = (void *)waitq, | |
5598 | .ctx = ctx, | |
5599 | .it = it, | |
5600 | }; | |
5601 | if (!it || !waitq) | |
5602 | return KERN_INVALID_ARGUMENT; | |
5603 | ||
5604 | ret = walk_setid_links(LINK_WALK_ONE_LEVEL, waitq, waitq->waitq_set_id, | |
5605 | SLT_WQS, (void *)&wctx, waitq_iterate_sets_cb); | |
5606 | if (ret == WQ_ITERATE_CONTINUE) | |
5607 | ret = WQ_ITERATE_SUCCESS; | |
5608 | return ret; | |
5609 | } | |
5610 | ||
5611 | /** | |
5612 | * iterator over all preposts in the given wqset | |
5613 | * | |
5614 | * Conditions: | |
5615 | * 'wqset' is locked | |
5616 | */ | |
5617 | int waitq_set_iterate_preposts(struct waitq_set *wqset, | |
5618 | void *ctx, waitq_iterator_t it, spl_t *s) | |
5619 | { | |
5620 | struct wq_it_ctx wctx = { | |
5621 | .input = (void *)wqset, | |
5622 | .ctx = ctx, | |
5623 | .it = it, | |
5624 | .spl = s, | |
5625 | }; | |
5626 | if (!it || !wqset) | |
5627 | return WQ_ITERATE_INVALID; | |
5628 | ||
5629 | assert(waitq_held(&wqset->wqset_q)); | |
5630 | ||
5631 | return wq_prepost_foreach_locked(wqset, (void *)&wctx, | |
5632 | wqset_iterate_prepost_cb); | |
5633 | } | |
5634 | ||
5635 | ||
5636 | /* ---------------------------------------------------------------------- | |
5637 | * | |
5638 | * Higher-level APIs | |
5639 | * | |
5640 | * ---------------------------------------------------------------------- */ | |
5641 | ||
5642 | /** | |
5643 | * declare a thread's intent to wait on 'waitq' for 'wait_event' | |
5644 | * | |
5645 | * Conditions: | |
5646 | * 'waitq' is not locked | |
5647 | * will disable and re-enable interrupts while locking current_thread() | |
5648 | */ | |
5649 | wait_result_t waitq_assert_wait64(struct waitq *waitq, | |
5650 | event64_t wait_event, | |
5651 | wait_interrupt_t interruptible, | |
5652 | uint64_t deadline) | |
5653 | { | |
5654 | wait_result_t ret; | |
5655 | thread_t thread = current_thread(); | |
5656 | spl_t s; | |
5657 | ||
5658 | if (!waitq_valid(waitq)) | |
5659 | panic("Invalid waitq: %p", waitq); | |
5660 | ||
5661 | if (waitq_irq_safe(waitq)) | |
5662 | s = splsched(); | |
5663 | waitq_lock(waitq); | |
5664 | ||
5665 | if (!waitq_irq_safe(waitq)) | |
5666 | s = splsched(); | |
5667 | thread_lock(thread); | |
5668 | ||
5669 | ret = waitq_assert_wait64_locked(waitq, wait_event, interruptible, | |
5670 | TIMEOUT_URGENCY_SYS_NORMAL, | |
5671 | deadline, TIMEOUT_NO_LEEWAY, thread); | |
5672 | ||
5673 | thread_unlock(thread); | |
5674 | waitq_unlock(waitq); | |
5675 | ||
5676 | splx(s); | |
5677 | ||
5678 | return ret; | |
5679 | } | |
5680 | ||
5681 | /** | |
5682 | * declare a thread's intent to wait on 'waitq' for 'wait_event' | |
5683 | * | |
5684 | * Conditions: | |
5685 | * 'waitq' is not locked | |
5686 | * will disable and re-enable interrupts while locking current_thread() | |
5687 | */ | |
5688 | wait_result_t waitq_assert_wait64_leeway(struct waitq *waitq, | |
5689 | event64_t wait_event, | |
5690 | wait_interrupt_t interruptible, | |
5691 | wait_timeout_urgency_t urgency, | |
5692 | uint64_t deadline, | |
5693 | uint64_t leeway) | |
5694 | { | |
5695 | wait_result_t ret; | |
5696 | thread_t thread = current_thread(); | |
5697 | spl_t s; | |
5698 | ||
5699 | if (!waitq_valid(waitq)) | |
5700 | panic("Invalid waitq: %p", waitq); | |
5701 | ||
5702 | if (waitq_irq_safe(waitq)) | |
5703 | s = splsched(); | |
5704 | waitq_lock(waitq); | |
5705 | ||
5706 | if (!waitq_irq_safe(waitq)) | |
5707 | s = splsched(); | |
5708 | thread_lock(thread); | |
5709 | ||
5710 | ret = waitq_assert_wait64_locked(waitq, wait_event, interruptible, | |
5711 | urgency, deadline, leeway, thread); | |
5712 | ||
5713 | thread_unlock(thread); | |
5714 | waitq_unlock(waitq); | |
5715 | ||
5716 | splx(s); | |
5717 | ||
5718 | return ret; | |
5719 | } | |
5720 | ||
5721 | /** | |
5722 | * wakeup a single thread from a waitq that's waiting for a given event | |
5723 | * | |
5724 | * Conditions: | |
5725 | * 'waitq' is not locked | |
5726 | * may (rarely) block if 'waitq' is non-global and a member of 1 or more sets | |
5727 | * may disable and re-enable interrupts | |
5728 | * | |
5729 | * Notes: | |
5730 | * will _not_ block if waitq is global (or not a member of any set) | |
5731 | */ | |
5732 | kern_return_t waitq_wakeup64_one(struct waitq *waitq, event64_t wake_event, | |
5733 | wait_result_t result, int priority) | |
5734 | { | |
5735 | kern_return_t kr; | |
5736 | uint64_t reserved_preposts = 0; | |
5737 | spl_t spl; | |
5738 | ||
5739 | if (!waitq_valid(waitq)) | |
5740 | panic("Invalid waitq: %p", waitq); | |
5741 | ||
5742 | /* NOTE: this will _not_ reserve anything if waitq is global */ | |
5743 | reserved_preposts = waitq_prepost_reserve(waitq, 0, | |
5744 | WAITQ_KEEP_LOCKED, &spl); | |
5745 | ||
5746 | /* waitq is locked upon return */ | |
5747 | kr = waitq_wakeup64_one_locked(waitq, wake_event, result, | |
5748 | &reserved_preposts, priority, WAITQ_UNLOCK); | |
5749 | ||
5750 | if (waitq_irq_safe(waitq)) | |
5751 | splx(spl); | |
5752 | ||
5753 | /* release any left-over prepost object (won't block/lock anything) */ | |
5754 | waitq_prepost_release_reserve(reserved_preposts); | |
5755 | ||
5756 | return kr; | |
5757 | } | |
5758 | ||
5759 | /** | |
5760 | * wakeup all threads from a waitq that are waiting for a given event | |
5761 | * | |
5762 | * Conditions: | |
5763 | * 'waitq' is not locked | |
5764 | * may (rarely) block if 'waitq' is non-global and a member of 1 or more sets | |
5765 | * may disable and re-enable interrupts | |
5766 | * | |
5767 | * Notes: | |
5768 | * will _not_ block if waitq is global (or not a member of any set) | |
5769 | */ | |
5770 | kern_return_t waitq_wakeup64_all(struct waitq *waitq, | |
5771 | event64_t wake_event, | |
5772 | wait_result_t result, | |
5773 | int priority) | |
5774 | { | |
5775 | kern_return_t ret; | |
5776 | uint64_t reserved_preposts = 0; | |
5777 | spl_t s; | |
5778 | ||
5779 | if (!waitq_valid(waitq)) | |
5780 | panic("Invalid waitq: %p", waitq); | |
5781 | ||
5782 | /* keep waitq locked upon return */ | |
5783 | /* NOTE: this will _not_ reserve anything if waitq is global */ | |
5784 | reserved_preposts = waitq_prepost_reserve(waitq, 0, | |
5785 | WAITQ_KEEP_LOCKED, &s); | |
5786 | ||
5787 | /* waitq is locked */ | |
5788 | ||
5789 | ret = waitq_wakeup64_all_locked(waitq, wake_event, result, | |
5790 | &reserved_preposts, priority, | |
5791 | WAITQ_UNLOCK); | |
5792 | ||
5793 | if (waitq_irq_safe(waitq)) | |
5794 | splx(s); | |
5795 | ||
5796 | waitq_prepost_release_reserve(reserved_preposts); | |
5797 | ||
5798 | return ret; | |
5799 | ||
5800 | } | |
5801 | ||
5802 | /** | |
5803 | * wakeup a specific thread iff it's waiting on 'waitq' for 'wake_event' | |
5804 | * | |
5805 | * Conditions: | |
5806 | * 'waitq' is not locked | |
5807 | * | |
5808 | * Notes: | |
5809 | * May temporarily disable and re-enable interrupts | |
5810 | */ | |
5811 | kern_return_t waitq_wakeup64_thread(struct waitq *waitq, | |
5812 | event64_t wake_event, | |
5813 | thread_t thread, | |
5814 | wait_result_t result) | |
5815 | { | |
5816 | kern_return_t ret; | |
5817 | spl_t s, th_spl; | |
5818 | ||
5819 | if (!waitq_valid(waitq)) | |
5820 | panic("Invalid waitq: %p", waitq); | |
5821 | ||
5822 | if (waitq_irq_safe(waitq)) | |
5823 | s = splsched(); | |
5824 | waitq_lock(waitq); | |
5825 | ||
5826 | ret = waitq_select_thread_locked(waitq, wake_event, thread, &th_spl); | |
5827 | /* on success, returns 'thread' locked */ | |
5828 | ||
5829 | waitq_unlock(waitq); | |
5830 | ||
5831 | if (ret == KERN_SUCCESS) { | |
5832 | ret = thread_go(thread, result); | |
5833 | assert(ret == KERN_SUCCESS); | |
5834 | thread_unlock(thread); | |
5835 | splx(th_spl); | |
5836 | waitq_stats_count_wakeup(waitq); | |
5837 | } else { | |
5838 | ret = KERN_NOT_WAITING; | |
5839 | waitq_stats_count_fail(waitq); | |
5840 | } | |
5841 | ||
5842 | if (waitq_irq_safe(waitq)) | |
5843 | splx(s); | |
5844 | ||
5845 | return ret; | |
5846 | } |